THE PHILIPPINE ELECTRONICS CODE
I. GENERAL RULES
1.1 PURPOSE OF RULES
1.2 APPLICABITY OF RULES
1.2.1 CONSTRUCTION AND RECOSNTRUCTION
A. SERVICE DROP
B. SUBORDINATE ELEMENT
C. REPLACEMENT
1.2.2 MAINTENANCE OF PLANT
1.2.3 CONSTRUCTION PRIOR TO THIS CODE
1.2.4 RECONSTRUCTION OR ALTERATION
1.3 SCOPE OF RULES
1.4 EQUIVALENTS
1.5 LIMITING CONDITIONS REQUIRED
1.6 EXEMPTIONS OR MODIFICATIONS
1.7 SAVINGS
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THE PHILIPPINE ELECTRONICS CODE
SECTION I
GENERAL RULES
1.1 PURPOSE OF RULES
The primary purpose of these rules is to establish, for the Republic of Philippines, uniform standards,
regulations and requirements for Electronics and Communications Design, planning manufacture,
production, fabrication, construction, installation, operation, and maintenance, the application of which
will insure adequate protection and safety to persons therein engaged and as well as in the provision,
operation and use of electronics and or communications components, devices, equipment, systems, plants,
stations, services, and or facilities. Application of the rules will also establish an acceptable level of
protection for electronics and communication devices, equipment, and plant from damages due to
electrical and/or physical hazards.
1.2 APPLICABILITY OF RULES
These rules apply to all electronics and/or communications design, planning, construction,
installation, manufacture, production, fabrication, operation, and maintenance, which comes within the
jurisdiction of this Code, located indoor or outdoor, terrestrially or extra terrestrially.
1.2.1
Construction and Reconstruction
The requirements apply to all devices, equipment, and plant constructed hereafter and shall become
applicable also to such components, equipment, devices, stations, plants, facilities, system and/or services
now existing, or any portion thereof whenever they are reconstructed.
The reconstruction of an element of a plant, station, system, or service requires that all elements
subordinate to the reconstructed element meet the requirements of these rules.
For the purpose of this Code, reconstruction will be constructed to mean that work which in any way
changes the identity of the station or plant or which it is performed excepting:
A. Ser vice Dr op
Service drops may be added to existing plant without necessitating changes in the circuit for
which they are originated.
B. Subordi nate El ement
An element added to an existing plant shall meet all requirements of these rules but does not
require any change in like elements already existing except where the added element is related to
existing like element. The plant or structure to which any subordinate element is added shall meet the
strength/safety factor.
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C. Replacements
Replacement of poles, towers, structure, or supports is considered to be reconstruction and
requires adherence to all strength and protection of this Code.
1.2.2
Maintenance of Plant
The plant or station shall be maintained in such condition to provide safety levels not less than the
minimum specified in rule 4.3.3. The plant or station, or portions thereof, constructed on or after the
effective date of this Code shall be kept in conformity with the requirements thereof.
The restoration of clearance and protection levels originally establish prior to the effective date of this
Code, where the original clearance or protection has been reduce by additional sagging or other causes, is
not considered reconstruction and the reestablish clearance or protection shall not be less than the original
clearance or protection at the time the plant or station was established. The changing of clearance or
protection for any other purpose is reconstruction and clearances or protection so changed shall comply
with the rules of this Code applicable to reconstruction.
1.2.3
Construction prior to the Code
The requirement of this Code, other than the requirement specified in Rules 1.2.2 and 1.2.4 do not
apply to plant or station constructed or reconstructed prior to the effective date of this Code. In all other
particulars, such plant or station or portions thereof shall conform to the requirements of the rules in effect
at the time of their construction or re-construction.
1.2.4
Reconstruction or Alternation
The Commission thru the appropriate government instrumentalities may order reconstruction or
alteration of existing plant or station or portions thereof whenever strength and electrical protection
requirement of this Code are not met and when public interest so requires.
1.3 SCOPE OF RULES
These rules are not intended as complete construction specifications, but embody only the
requirements which are most important from the standpoint of safety and protection. Construction shall be
according to accepted or established good practices for the given local conditions in all particulars not
specified in the rules.
1.4 EQUIVALENTS
Wires sizes specified in this Code may be substituted with its nearest metric equivalent. Copper wire
may be substituted with aluminum, copper clad steel, or other make/materials provided the currentcarrying capacity is identical.
Flat or braided copper may be substituted for round or stranded copper wire provided the currentcarrying capacity is not less than that of the latter.
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1.5 LIMITING CONDITIONS SPECIFIED
The requirement specified in these rules as to clearance, strength and protection are limiting
conditions expressed as minimum or maximumvalues, as indicated. In cases where two or more
requirements establish limiting conditions, the more or most stringent condition shall apply, thus
providing compliance with other applicable conditions. Greater strength of construction, more ample
clearances and higher protection level may be desirable or practical in some cases, and may be provided
accordingly if other requirements are not violated in so doing.
1.6 EXEMPTIONS MODIFICATIONS
If in a particular temporary and emergency case wherein a special type of construction, exemption
from or modification of any of the requirements herein is desired, the Commission shall consider an
application for such exemption or modification only when accompanied by a full statement of conditions
existing and the reason why such exemption or modification is asked and is believed to be justifiable. It is
to be understood that unless otherwise ordered, any exemption or modification so granted shall be limited
to the particular case or the special type of construction specifically covered by the application.
1.7 SAVING CLAUSE
The Commission reserves the right to change any of the provisions of this Code in specific cases
when, in the Commission‟s opinion, public interest shall be served by so doing.
Compliance with these rules and regulations shall not relieve a utility firm, entity, person or group of
persons from compliance with any statutory requirement.
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SECTION II
DEFINITIONS OF TERMS AS USED IN THE RULES
OF THIS CODE
This section defines technical terms as used in the rules of this Code. The meanings of some terms differ
with the field in which they are used, thus requiring more than one definition. Definitions contained in
this section have been restrictively worded to emphasize the special purpose they are used in this Code.
ACCESS

A point of entry or a means of entry into a circuit.
ACCESIBLE

Admitting close approach because not guarded by locked
doors, elevation or other effective means.
ACCESSIBLE PART

A part so located that it can be contacted by a person, either
directly or by means of a probe or tool, or that is not
recessed the required distance behind an opening.
ACCESSORIES

Devices that performs a secondary or minor duty as an
adjunct or refinement to the primary or major duty of unit
of equipment.

The science of sound.

The physical pain, dizziness, and sometimes nausea caused
by hearing a sudden very loud sound. The threshold of pain
is about 120 dBm.
AGING

The changes in properties of a material in time.
AIR GAP

A separating space between two magnetic materials or
conductors.
ALARM

A visual or audible signal which alerts personnel to the
existence of an abnormal condition.
ALIVE

To have an electrical potential or charge different from that
to earth.

A type of telephone cable sheath featuring a corrugated
aluminum tape applied longitudinally and a polyethylene
jacket overall.
ACOUSTICS
ACOUSTIC SHOCK
ALPETH
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AMERICAN WIRE GAUGE
(AWG)

A scale of cross sectional measurement for non-ferrous
(copper, bronze, aluminum, etc.) wires.
AMPERE-HOUR

The quantity of electricity represented by a current of one
ampere that flows for one hour.
ANCHOR

Any device which holds something secure; a device buried
in the ground to which anchor rods and guys are fastened.
ANHYDROUS

Dry; containing no water.
ANTENNA

A means for radiating or receiving radio waves.
APPLIANCE

Any device that uses or needs electrical or usually an
electric current supply to perform a certain function or
operation; any equipment, usually complete in itself, that
transforms electric energy into another form usually aural,
visual, heat, or motion at the point of utilization.
ARRESTER

Device which diverts high transient voltage to ground and
away from the equipment thus protected; the voltage
limiting portion of a protector.
ARRESTER GAS-FILLED

Protector consisting of opposing spaced metal electrodes
within a sealed tube or enclosure filled with gas such as
neon or argon.
ASSEMBLY

A grouping of components to accomplish a particular
function.
ATMOSPHERE,
EXPLOSIVE

Air holding in suspension dust, metal particles of
flammable gas in such proportions that may ignite
explosively.
ATTACHMENTS

All of the plant elements (cables, cross-arms, brackets, etc.)
which are fastened to a supporting structure such as a pole.
AUDIO

Pertaining to frequencies which can be heard by the human
ear.
AUTOMATIC

Describing the actions of a device or equipment which are
taken without human supervision in response to certain to
pre-determined conditions.
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BACKBONE

The main system route, usually the route carrying the
majority of the traffic, ad often the longest series of
cascaded hops.
BANDWIDTH

Range of frequencies of a device, within which its
performance, in respect to some characteristics conform to
some specified limits; the difference between the upper and
lower limits of the operating frequency of the device.
BASEBAND

Band of frequencies occupied by aggregate of all the
information signals use to modulate a carrier.
BATTERY

A group of two or more cells connected together to furnish
current by conversion of chemical, thermal, solar or nuclear
energy into electrical energy. Common usage permits this
designation to be applied also to a single cell.
BOND

A low resistance electrical connection between two cable
sheets, between two ground connections or between similar
parts of two circuits.
BUS

A conductor or group of conductors, that serves as a
common connection for two or more circuits.
CABLE

Assembly of insulated conductors into a compact form
which is covered by a flexible, waterproof, protective
covering.
CIRCUIT

(1) The complete electrical path between terminals over
which telecommunications are provided; (2) A network of
circuit elements: resistances, reactances, semiconductors
etc. to perform a specific function.
CLIMBING SPACE

The vertical space reserved along the side of a pole or
tower to permit ready access for linemen to equipment and
conductors located thereon.
CONDUCTOR

Anything such as a wire or cable which is suitable for the
carrying of an electric current.
COMMUNICATION

(1) Transmitting and/or receiving of information signals, or
messages between two or more points; (2) the information
thus received.
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dB

Abbreviation for “decibel”, which is one-tenth of a bel. A
unit expressing the ratio of two voltages, currents or
powers. It is equal to 20 times the common logarithm of the
ratio of the two voltages or two currents and 10 times the
common logarithm of the ratio of the two powers.
DROPWIRE

Insulated wires, used to run a subscriber‟s line from the
terminal on the pole to the protector at the house of the
building.
ELECTRONICS

The branch of science and technology which deals with the
control and utilization of electron flow.
ELECTRONIC
SWITCHING

The
selective
interconnection
of
channels
of
communication by means consisting essentially if not
entirely of electronic circuitry and circuit elements.
EXPLOSION ROOF

One that is designed and constructed to withstand an
explosion of a gas or vapor that may occur within it or in its
immediate vicinity and to prevent the ignition of the gas or
vapor surrounding or within its enclosure.
EXPOSED PART

A part which can be inadvertently touched or approached
nearer than a safe distance.
FACILITY

Anything used or available for use in the furnishing of
communication service.
FACILITIES

The elements used or available for use in the furnishing of
communication service, such as radio facilities, outside
plant facilities, indoor plant facilities etc. The term does not
normally include the customer‟s equipment.
FAULT

A physical condition that causes a device, a component or
an element to fail to perform in a required manner.
FAULT CURRENT

A current that flows from one conductor to ground or to
another conductor owing to any abnormal connection
(including an arc) between the two.
FLAME ROOF

Apparatus so treated such that it will not maintain a flame
or will not be injured readily when subjected to flame.
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FLAME RETARDING

Property of materials or structures such that they will not
convey flame or continue to burn for longer times than
specified in the appropriate flame test.
FLASHOVER

A discharge through air, around or over the surface of solid,
liquid or other insulation, between parts of different
potential of polarity, produced by the application of voltage
such that the breakdown path becomes sufficiently ionized
to maintain an electric arc.
FUSE

A device used for protection against excessive currents.
Consisting of a short length of fusible metal strip which
melts when the current through it exceeds the rated amount
for a definite time.
GROUND

A conducting connection, whether intentional or accidental,
by which an electric circuit or equipment is connected to
the earth, or to some conducting body of relatively large
extent that serves in place of the earth.
GROUND BUS

A bus to which the grounds from individual pieces of
equipment are connected, and that, in turn, is connected to
ground at one or more points.
GROUND RING

A configuration of grounding conductors arranged around a
structure such as building, tower footing, tower guy, anchor
etc. normally connected to an earth ground at one or more
points.
GUY

A tension member (of solid or stranded wires) used to
withstand an otherwise unbalance force on a pole or other
overhead lines structures.
GUY, OVERHEAD

A guy extending from a pole or structure to a pole structure
or tree and is sometimes called a span guy.
GUY, ANCHOR

A guy which has its lower anchorage in the earth.
GUY EXPOSED

A guy which has any part less than 2.5 meters from the
vertical plane of any electric power conductor of more than
250 volts.
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GUY IN PROXIMITY

A guy which has any part within a vertical distance of less
than 2.5 meters from the level of power conductors and a
radial distance of less than 1.8 meters from the surface of a
wooden pole or structures.
GUARDED

Covered, shielded, fenced, enclosed, or otherwise protected
by means of suitable covers, or casings, barriers, rails or
screens, or platforms to remove the likelihood of dangerous
contact with or approach by persons or objects to a point of
danger.
HANDHOLE

An opening in an underground run or system into which
workers reach, but do not enter. A sub-surface box having a
cover flush with the ground.
HAZARD

Any condition which imperils life, limb and property.
INSULATED

Separated from other conducting surfaces by a dielectric
substances or air space permanently offering a high
resistance to the passage of current and to disruptive
discharge through the substance or space. When any object
is said to be insulated, it is understood to be insulated in
suitable manner for the conditions to which it is subjected.
Otherwise, it is, within the purpose of this Code,
uninsulated.
JOINT USE

Occupancy of poles or structures by two or more different
entities by mutual agreement.
LIGHTNING ARRESTER

A device designed to protect apparatus from high transient
voltage, by diverting surge current to ground and capable o
repeating this function as specified.
LINES,
COMMUNICATION

The channels or conductors and their supporting or
containing components or structures usually located
outdoors which are used for transmission/reception of
information/intelligence
in
communication
service
(telephone, telegraph, data telemetering, video, etc.).
LINE, POWER

The conductors and their supporting or containing
structures which are located outdoors used for transmitting
a supply of electrical energy.
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MAINTENANCE

All of the work required to keep the plant, circuits, lines,
facilities, systems and services up to standards. This
includes testing, trouble clearing, repairing, and replacing
defective elements.
MANHOLE

A subsurface chamber, large enough for a person to enter,
in the route of one or more conduit runs, and affording
facilities for placing and maintaining in the runs,
conductors, cables, and any associated apparatus.
MANUAL

Operated by mechanical force, applied directly by personal
intervention.
MESSENGER

Stranded steel wires in a group which generally is not a part
of the conducting system, its primary function being to
support wires or cables of the system.
NOISE

Any unwanted disturbance in a communication system
which tends to obscure the clarity and validity of a signal in
relation to its intended end use.
OPERATING CONTROL

A control, usually a knob, pushbutton or lever, provided to
enable the user to cause the appliance to perform its
intended function, without the use of tools, when the
appliance is in normal operating condition.
PLANT

A general term applied to the whole or portion of the
physical property of a communication company which
contributes to the furnishing of communication service.
PLANT, INSIDE

All plant which is inside of building.
PLANT, OUTSIDE

All plant which is “out of doors” not in building, such as
poles, conduits
underground.
cables,
etc.
installed
overhead
or
PRACTICABLE

Capable of being accomplished by reasonably available and
economic means.
PROTECTOR

A device which provides protection from over-voltage
and/or over-current.

A protector whose voltage limiting element utilizes carbon
blocks.
PROTECTOR,
BLOCK
CARBON
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PROTECTOR, GAS TUBE

A protector whose voltage limiting element employs
electrodes in a gas filled (neon, argon, etc.) envelope.
QUALIFIED

Persons trained and authorized for the construction,
maintenance and operation of the apparatus, circuit or
system and responsible for the safety precautions involved.
RADIANT ENERGY

Any energy which radiates in the form of radio waves,
infrared (heat) waves, light waves, X-rays, etc.
RADIATE

The spreading out of radiant energy.
ROD, GROUND

A metallic rod, driven into the ground to provide an
electrical connection to the earth.
ROD, LIGHTNING

A metallic rod carried above the highest point of a pole or
structure and connected to earth by a heavy copper
conductor intended to carry lightning currents directly to
earth.
RECONSTRUCTION

That work which in any way changes the identity of the
plant or stations or portions thereof.
SERVICE DROP

The installation from the terminal on the pole to the
protector at the customer premises.
SAG

The maximum departure, measured vertically, of a wire or
cable in a given span from a straight line between the two
points of support of the span at 60° C and no wind loading.
SPAN

The horizontal distance between two adjacent supporting
points of a cable or wire.
SUPPLY CIRCUIT

The branch circuit supplying electrical energy to the
equipment or appliance.
SYSTEM, ELECTRONIC

A configuration or arrangement of one or more electronic
equipment producing the desired performance.
TELECOMMUNICATION

Any transmission, emission or reception of signs, signals,
writings, images, sounds or intelligence of any nature by
wire, radio, visual, or other system that may in the future
become known or developed.
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TENSILE STRENGTH

The pulling stress required to break a material, such as a
wire, express in kilograms of stress per cross-sectional area.
TENSION

Mechanical stress caused by forces which tends to stretch
or severe the material stressed.
TENSION, MAXIMUM
ALLOWABLE

One half of the tensile strength for the messengers guys,
etc. and one fourth of the tensile strength for
communication cables and wire.
TENSION, MAXIMUM
WORKING

The tension resulting under theconstruction arrangement
with the maximum loading conditions specified in section
4.
TOWER DISPLACEMENT

The horizontal displacement of a point on the tower axis
from its no-wind load position at that elevation.
TOWER SWAY

Tower sway at any specified elevation shall be defined as
the angular displacement of a tangent to the tower axis at
the elevation from its no-wind load position at that
elevation.
TOWER TWIST

Tower twist at any specified elevation shall be defined as
the horizontal angular displacement of the tower from its
no-wind position at that elevation.
UNDERGROUND

Describing communication facilities installed below the
surface of the earth.
WORKING SPACE

The space extending laterally from the climbing space,
reserved for working below, above between conductor
levels; the space surrounding a device or equipment.
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III. GENERAL ELECTRICAL PROTECTION AND
GROUNDING REQUIREMENTS
3.1 GENERAL
3.1.1 Objective
3.1.2 Lightning
3.1.3 Power Contact / Induction
3.1.4 Acoustic Shock
3.1.5 Electric Shock
3.2 PROTECTION METHODS
3.2.1 Shielding
3.2.2 Voltage Limiting
3.2.3 Current Limiting and Interrupting
3.2.4 Grounding
A. Purpose
B. Ground Resistance
C. Made Ground
3.3 METHODS AND MATERIALS
3.3.1 Lightning Rods
3.3.2 Fuses
3.3.3 Surge Arrester
3.3.4 Grounding and Bonding
3.4 MEASUREMENTS
3.4.1 Ground Resistance Test Methods
3.4.2 Earth Resistivity
3.4.3 Determining Good Electrode Location
3.4.4 How to Improve Grounds
3.5 MAINTENANCE AND INSPECTION
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SECTION III
GENERAL ELECTRICAL PROTECTION AND
GROUNDING REQUIREMENTS
3.1 GENERAL
Electrical protection measures covered in this Code are directed against the effects of lightning,
accidental contact with power lines, voltages/electromagnetically/electrostatically induced into
communication circuits by normal or fault currents in parallel runs of power lines and, also, local earth
potential rises due to the flow of lightning or power fault currents.
3.1.1 Objective
Communication systems are subject to electrical hazards from exposure to lightning and power
systems and unless adequate protection measures are employed, such exposures may result in loss of life,
service interruptions and excessive maintenance expense.
A. The primary considerations of electrical protection are:
a)
to minimize, as far as practicable, electrical hazards to persons engaged in construction,
operation, maintenance or use of communication systems;
b)
to reduce, as far as practicable damage to equipment and plant;
c)
to eliminate, as far as practicable, any fire hazard resulting from the operation of
communication systems; and,
d)
to minimize, as far as practicable, acoustic shock hazards to anyone using communication
services.
B. The amount of protection to be adopted and employed is determined by a proper balance
between:
a)
the cost of protection measures employed plus the amount required to maintain the
protection level and adopted; and,
b)
the value of damage to or loss of life and property and/or that of service interruptions
caused by electrical hazards.
C.Protection measures may be more costly or impractical to add on or to an operating plant, so, it is
desirable to consider protection requirements in the initial setting-up of the plant.
D.The standards specified in the Code evolves around optimum protection, explain in 3.1.1.B, but
sometimes the state of the art progresses and new techniques evolve that meet the intent of the Code
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much more effectively that its own specific requirements, and in such cases, additional protection may
be use provided no provision in this code is violated.
E. When the safeguarding od human life is involved, even if not actually required by this Code,
communication entities should update its practice voluntarily and as soon as possible rather than wait
for the revision.
3.1.2Lightning
Lightning is an electrical discharge which occurs between clouds and also from cloud to earth. It is
latter type of discharge that is of concern in this Code.
A. Lightning surges can appear in various parts of a communication system and produce explosive
effects, dielectric failure and fusing of conductors.
B. The path lightning takes depends upon the impedance presented to its wave front. With a wave
that rises from zero to crest value in from 1 and to 10 micro-seconds, the wave front appears to be a
signal whose frequency is from 25 to 250 KHZ.
C. Lightning behaves very much like radio frequency voltages and as much as such its behavior
can be predicted fairly accurately and protection measures can be selected, considering this
characteristic.
D. Lightning surges may reach indoor equipment and circuits thru exposed portions of the
communication system such as antenna towers, transmission lines, telephone cables, etc. Lightning may
reach buried plants by a direct stroke on portions of the plant exposed above ground and by arcing to
the plant from ground thru plant, trees, man-made structures or the ground itself.
3.1.3. Power Contact/I nduction
The necessity for constructing power and communications facilities near each other and the
advantages to both interest of joint occupancy of poles and support structures present power
contact/induction problems that must be carefully considered.
A. Good construction and adequate spacing between power and communication facilities are the
first line of defense against power contact and power induction hazards. This essentially keeps foreign
potential out of the communication plant.
B. The second measure is to provide paths to ground on the communication facilities sufficient to
prevent excessive voltage rise in the communication plant and utilization of current limiting devices.
C. Insulation on communication conductors may in many instances withstand secondary power
potentials but dependence on insulation alone introduces a considerable hazed.
D. Where the possibility of a power line contact is eminent, equipment connected to such lines shall
be provided with protectors capable of discharging sufficient current to fuse the line conductor, or they
shall be provided with lines fuses and surge arresters. Such protectors shall be adequately grounded to
prevent excessive rise in potential at the equipment locations.
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E. Communication control circuits to electric power stations are always required to function more
so during periods when there are faults on the power systems, so adequate protection is required.
F. A disturbance affecting communication circuits serving electric power stations is ground
potential rise at the power stations. This potential is developed between the power station ground and
the remote ground during periods when large ground currents, such as phase to ground fault currents are
flowing in the station ground. The magnitude of this potential is the product of the ground current and
the ground impedance.
G. Isolating transformers and/or neutralizing transformers and or other appropriate devices should
be utilized to prevent disturbance in communication circuits exposed to a rise in ground potential.
3.1.4Acoustic Shock
Acoustic shock results from an abnormally high sound level, the physical effects of which may vary
from minor discomfort to serious injury.
A. Voltage surges on the communication plant initiated by foreign potential, principally lightning,
constitute the major hazard, although switching transients may also be the cause.
B. To reduce the effect of acoustic shocks, a device consisting of two rectifiers, or other semiconductor elements in parallel with opposite polarities, shall be connected across the telephone receiver
or headset.
C. The device shall meet the following:
a) It should occupy a small space, so that it can be placed, for example, in the case of the
telephone receiver capsule.
b) Its electrical characteristics should not show significant changes under the temperature and
humidity conditions to which it is subjected in service.
c) It should not degrade the performance of the circuit it is connected to.
d) It should operate such that the amplitude of the sound pressure caused by the diaphragm of
the telephone receiver does not exceed 120 dB above 2 × 10 -4microbar at 1000 Hz.
3.1.5 El ectri c shock
Current through the body rather than voltage of the circuit determines electric shock intensity. Voltage is
significantly only in so far as it is one of the factors determining the magnitude current.
A. Shock current is also dependent on the impedance of the circuit contacted plus the body
impedance of the victim.
B. Studies have shown that the average resistance of a dry adult human body is approximately
1,000,000 ohms. Wet or damage skin reduces this figure and 1,500 ohms is a conservative figure
representing the body resistance for safety calculations.
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C. Ventricular fibrillation is likely to occur when a 60 Hz rms. Current of 0.030 amperes and
above passes through one‟s chest cavity. Because of this, ANY CIRCUIT FROM WHICH IN
EXCESS OF 30 MA RMS AC OR 90 MA DC CAN BE DRAWN THROUGH A 1500 OHM
RESISTOR (45V RMS AC OR 135VDC) SHALL BE CLASSIFIED AS HAZARDOUS.
D. THE POTENTIAL DIFFERENCE AT ANY TIME BETWEEN ANY EXPOSED
STRUCTURE (EQUIPMENT CABINETS, HOUSINGS, SUPPORTS, ETC.) TO GROUND
(FLOOR, EARTH, ETC.) OR BETWEEN ANY EXPOSED STRUCTURE WITHIN THE REACH
OF AN ADULT PERSON (AOOROX. 1.5 METERS) SHALL BE NO GREATER THAN 45
VOLTS RMS AC OR 135 VOLTS DC.
E. THE POTENTIAL DIFFERENCE AT ANY TIME BETWEEN TWO POINTS ON THE
FLOOR OR EARTH SURFACE SEPERATED BY A DISTANCE OF ONE PACE, OR ABOUT
ONE METER, IN THE DIRECTION OF MAXIMUM POTENTIAL GRADIENT SHALL BE NO
FREATER THA 45 VOLTS RMS AC OR 135 VOLTS DC.
F. The limits specified in 3.1.5 D, and 3.1.5 E concern only the safety of personnel and should not
proper equipment performance.
3.2 PROTECTION METHODS
Rarely will it be economically feasible to meet protection requirements for all situations by means of
basic insulation incorporated in the design of equipment and plant. Additional protection measures are
usually required and may use one or combination of the following basic protection measures.
3.2.1 Shielding
Shielding is the provision of a grounded electrical conducting material located such that foreign potential
will be intercepted and surge currents diverted to ground with the least damage to plant equipment
possible. Parallel or conductivity is essentially similar to shielding since a parallel conducting path is
provided to absorb surge current which otherwise can flow and cause damage to communication
plant/equipment.
3.2.2 Voltage L imiti ng
Voltage limiting prevents development of hazardous potential difference in communication plant by
direct bonding, when permissible or by use of surge current, discharges gaps, diodes, etc. which operate
under abnormal voltage condition.
3.2.3 Current Limiti ng and I nterr upting
Current in a circuit can be kept from rising above a predetermined value by the use of a fuse in series
with the circuit. When current flows through a fuse for a specified time with a magnitude greater that its
rating, the fuse will interrupt the current.
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3.2.4Groun ding and Bondin g
The foreign potential has entered the communication plant, the extent of possible damage will be
reduce if some means are available for its rapid removal such as low impedance paths to ground at. Or
close to. the point of entry.
A. Purpose
Grounds or connections thereto are used to divert undesired currents before they reach the
equipment being protected and often are installed both at and some distance away from the protected
equipment. When the difference of pote ntial between the “grounded plant” and remote earth does not
exceed the breakdown potential of the plant and does not present a shock hazard, the plant is
adequately grounded.
B. Gr oun ded Resistance
Ground resistance is the is the resistance path of a ground connection which includes the ground
wire and its connection to ground electrode. the ground electrode, the contact between the electrode
and the earth and surrounding soil. This value should be kept as low as feasible and should NEVER
EXCEED 5.0 OHMS FOR EQUIPMENT LOCATIONS, ANTENNA TOWERS,AND ALL ALLIED
INSTALLATIONS, AND 25 OHMS FOR OUTSIDE PLANT TELEPHONE POLES AND
MANHOLES AS WELL AS CUSTOMER PREMISES.
C. M ade Groun d
A made ground is an electrode buried in the ground for the purpose for establishing a low
resistance electrical contact with the earth. Types of made grounds include driven rods, driven pipes,
buried plates, buried cones, or other similar devices placed in the ground.
3.3 METHODS AND MATERIALS
Electrical protection usually employs one or a combination of two or more methods to attain a sufficiently
reliable level or safety. The basic idea is to keep foreign potential out of the communication facility or
plant or when it manifest itself in the communication facility, it should be diverted to ground as near the
point of entry and at the shortest time possible.
3.3.1 L ightnin g Rod
Structures do not influence the mechanism or path of a thunder-storm. Tall structures, such as antenna
towers, only provide a favorable discharge point for lightning that would otherwise strike the earth in the
vicinity of the structures if they were no present.
A. The area within which strokes are likely to be diverted to a structure varies with the structure‟s
effective height. This area for the purpose of this Code shall be a cone having a radius of three times the
effective height is measured from the top of the structure to the level of the point being considered.
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B. The material for the lightning rod shall be of galvanized iron/steel, copper weld or other
corrosion-resistant material. The material selected shall be resistant to any corrosive condition existing
at the installation or shall be suitably protected against corrosion.
C. Lightning rods shall be mounted atop structures not less than 30 cm. above the highest point of
the structure or not less than 30 cm. above the point which creates an effective electrical height for the
structure and to encompass all other elements, mounted and protruding horizontally from the structure,
within the area explained in 3.3.1 A.
D. A No. 2 AWG grounding conductor connected to the lightning rod shall be run in the shortest
route directly to the master ground bus or direct to earth without intervening splices or connection, free
from sharp bends. Each lightning rod shall require a separate of # 2 AWG grounding conductor.
E.Structures not requiring lightning rod installations are:
a) Structures within the area described in 3.3.1.A. due to nearby taller buildings or structures.
b)Passive reflectors and other similar fully metallic structures. Provided that its footing or a
connection to a separate made ground provides sufficient grounding for the structure and that
provision 3.1.5 D. is not violated.
c) Metallic antenna towers or poles where the antennas and their supports mounted on the
metallic tower or pole have electrical continuity all the way from all elements to the structure and
its footings and where a connection to a separate made ground provides sufficient grounding for
the structures and provided further that provision 3.1.5. D. is not violated.
F. All other structures not covered by provision 3.3.1.E. shall be provided with lightning rod or
rods as required considering provision 3.3.1.C.
G. The grounding system of lightning rods shall not be used as grounding conductors for any part
of a plant.
3.3.2 F uses and Cur rent I nterr uptin g
Current interrupting may be accomplished by employing one or any combination of the following:
a)Fuse Link (fuses)
b) Heat coils
c) Fuse cable
d) Automatic circuit breaker
A. Fuses are effective only when its time and current operating characteristics are matched to that
of the circuit it is intended to protect.
B. After the fuse has opened, an arc may persist under the influence of excessive voltage. Failure
of the arc to clear rapidly constitutes hazard and defeats the purpose of the fuse.
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THE PHILIPPINE ELECTRONICS CODE
C. Fuses are not effective for limiting short duration surges so it becomes necessary to provide
some means of diverting surge currents through other paths having adequate current carrying
capacity.
D. Heat coils that guard against “sneak current” fire hazard and will carry 0.35 ampere for about
three hours and will operate within 210 seconds and 0.54 ampere.
E. Fuse cables are telephone cable sections installed in series and prior to the plant being
protected and are one size smaller than the section to which they are connected.
F. An automatic circuit breaker is a device which opens the circuit when the current exceeds a
predetermined rating a specified time without causing injury to itself and capable of being reset when
a default condition no longer exist.
G. The choice of current interrupting device or method shall consider the cost of the protection
measure/s against the value of service continuity and cost of system damage but personnel safety shall
never be jeopardized.
3.3.3 Surge Ar r esters
Surge Arresters are normally open circuited devices and pass no significant current at normal
operating potentials and shall meet the following fundamental requirements:
A. Striking voltage must be as constant as possible even after several successive discharge.
B. The transition from glow to arc discharge must occur at less than one ampere. Are discharge,
once established, must be very stable, and spontaneous transition from an arc to glow discharge must
never occur.
C. The arcing voltage must be as small as possible.
D. It must be capable of carrying several tens of amperes for periods of the order of one second. It
must be able to repeat such operation several times at very short intervals without its characteristics
being affected.
E. If the above are exceeded, the surge arrester must “fail safe”, this shall be achieved through
final short-circuiting of the electrodes. The surge arrester must never be destroyed by shattering of the
enveloped in such a way as to leave the electrodes exposed, or by breakage of an internal connection,
since in such cases the circuit is no longer protected and no warning of the fact is given.
F. The choice of breakdown voltage rating of surge arrester shall be as low as may possible be
allowed by the facility to which it is to be connected.
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3.3.4 Grounding and B onding
A. A properly designed grounding system shall result in the following:
a) Limiting to definite value the potential to earth of the entire communication system by
maintaining some point in the system at earth potential. Limiting the voltage to which the system to
ground insulation is subjected results in fixing the insulation rating of system components.
b) Keeping the voltage to ground of metallic enclosures and other structures that may be
contacted by personnel to values safe for personnel.
c) Protecting against static electricity with its attendant shock and fire hazards.
d) Providing a low impedance path for currents, induced due to direct contact of the
communication plant with lightning and/or electrical power systems.
B. No cutout switch or fuse shall be placed in the ground lead.
C. The copper grounding conductors should be insulated to allow continuity testing at the time of
installation and periodically thereafter.
D. Ground conductors should be run only in NON-METALLIC conduit or not in conduit. When the
use of metallic conduit cannot be avoided, the grounding conductor shall be bonded to both ends of the
conduit.
E. For radio stations, telephone/telegraph offices, Computer/DATA centers & the like except
telephone/telegraph/telex subscriber stations, data terminals and residential installations, WATER PIPE
GROUND SHALL BE AN ADDITION TO THE PRIMARY (MADE GROUND) GROUNDING
ELECTRODE SYSTEM AND SHALL NOT BE A SUBSTITUTE FOR IT, OR VICE VERSA.
F. Ground wiring shall be as short as possible without sharp bends and kinks.
G. All elements of the communication plant designed to be at ground potential shall be bonded
together.
3.4 MEASUREMENTS
Because formulas for ground resistance are complicated and earth resistivity is neither uniform nor
constant, direct measurement of ground resistance is needed.
Gr oun d Resi stance Test M ethods
3.4.1 Ground resistance measurement procedures are simple and straightforward and instruments are
mostly direct reading. Two basic test methods for ground resistance measurement are:
(a)Direct method or two terminal test.
(b)Fall of potential method or three terminal test.
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A.The direct method is the simplest way to make an earth resistance test. With this method, resistance
of two electrodes in series is measured the electrode under test and the reference ground or water system.
There are three important considerations with this test method:
1) The reference ground or water systems must be extensive enough to have negligible
resistance.
2) The water pipe must be metallic throughout without any insulating couplings or flanges.
3) The earth electrode under test must be far enough away from the water-pipe system to be
outside its sphere of influence.
Fig. 3-1Connections for a dir ect or two termi nal gr ound r esi stance test.
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B. The Fall of Potential method uses two reference rods. Placing of the two reference rods is critical
and the instruction of the instrument manufacturer must be followed.
Fig. 3-2 Connections for a F all of Potenti al or Thr ee Termi nal Groun d Resistance Test.
Fig. 3-3F all of potenti al method of testi ng.
C. Other methods for ground resistance measurements may be used such as Voltmeter-ammeter
Method and Triangular method, provide the limitations of each method are considered and due safeguards
taken.
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3.4.2 Ear th Resistivity
Earth Resistivity expressed in ohm-centimeter is the resistance of parallel faces of a one cubic centimeter
of soil. Actually the earth is a poor conductor of electricity compared to copper, but, if the area of a path
for current is made large enough, resistance can be quite low and the earth can be a good conductor.
A. Different types of soil exhibits different resistivities. This is shown is the following table.
Table 3-1  RESISTIVITIES OF DIFFERENT SOILS
Resi sti vity, Ohm- Cm
Type of Soil
Average
M in
M ax
Fill; ashes, cinders, brine, wastes
2,370
590
7,000
Clay, shale, gumba, loam
4,060
340
16,300
15,800
1,020
135,000
94,000
59,000
Same with varying proportions
of sand and gravel
Gravel, sand, stones, with little
clay or loam
From: US Bureau of Standards Technical Report 108
 -  RESISTIVITIES OF DIFFERENT SOILS
Type of Soil
Surface soil, loam
Clay
Sand and Gravel
Surface limestone
Limestone
Shales
Sandstone
Granites, basalts, etc.
Slates, etc.
Resi sti vity, Range, Ohm- Cm.


100
200
5,000
10,000
500
500
2,000
5,000
0,000

100,000
 1,000,000
00,000

10,000
 00,000
100,000
1,000
From: Evershed & Vignoles Bulletin 245
25

0,000
458,000
THE PHILIPPINE ELECTRONICS CODE
B. In soil, conduction of current is largely electrolytic so the amount of moisture and salt content of
the soil radically affects its resistivity. Amount of water in the soil varies with the weather, time of the
year, nature of sub-soil and depth of the permanent water table.
 -     
M oistur e Content
Resistivity, Ohm-Cm.
% by weight
Top Soil
0
2.5
5
10
15
20
30
Sandy Loam
1000 × 106
1000 × 106
250,000
150,000
165,000
43,000
53,000
18,500
19,000
10,500
12,000
6,300
4,200
6,400
From: “An Investigation of Earthing Resistance” by P.J. Higgs I.E.E.E.
Jour., vol. 68, p. 736, Feb. 1930.
Pure water has a high resistivity; naturally-occurring salts in the earth, dissolve in water, lower its
resistivity.
 -     
Added Salt % by Wei ght
of M oistur e
Resistivity, Ohm-Cm.
0
0.1
1.0
5
10
20
10,700
1,800
460
190
130
100
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C. An increase in temperature will decrease resistivity because water in soil mostly determines the
resistivity and an increase in temperature decreases the relativity of water. This is shown in the following
table.
 -  EFFECT OF TEMPERATURE ON EARTH RESISTIVITY
Temper atur e
C
20
10
0
0
-5
-15
Resi sti vity, Ohm- Cm.
F
68
50
32 (water)
32 (ice)
23
14
7,200
9,900
13,800
30,000
79,000
330,000
D. Earth resistivity is a very variable quantity and to determine the value at a given location at a
given time, the only sure way is to measure it.
E. The deeper ground electrode gives a more stable and lower value of resistance. Electrodes must
reach deep enough level to provide permanent moisture content and stable temperature.
Determ in in g Good El ectrode L ocati on
3.4.3 A good low-resistance ground electrode depends upon a low-resistivity soil in a location where the
electrodes can be driven. There are two approaches to picking this location:
a) Drive rods in various locations to such depths as may be required and measure the resistances
while the rods are being driven.
b)Measure the earth resistivity before driving ground rods then calculate the number and length of
rods required.
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H ow to impr ove gr ounds
3.4.4When the ground-electrode resistance is not low enough, undertake the following:
A. Lengthen the ground-electrode in the earth
Fig. 3-4 Ear th r esistance decreases wit h depth of electr ode i n earth .
B. Use multiple Rods.
Fig. 3-5 Comparati ve r esi stance of mu lt ipl e r od eart h electrodes.
Singl e r od equal 100%
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Fig. 3-6 Ef f ect of vari ation i n ear th r esistivity wi th depth on th e resistance
of a hor i zontal gr ound 150 meter s l ong and 0.4 cm, diameter bur ied
at th e sur f ace.
Fig. 3-7 Vari ation of r esistance of ver tical gr ound rod with l ength f or
vari ous diameter s as i ndi cated on cur ves, for an ear th r esi sti vity
of 100 meter-oh ms.
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Fig. 3-8 Vari ation of r esistance of hor izontal ground with length ground
at the sur f ace and at a depth of 30 cm, f or an eart h r esistivi ty of
100 meter-oh ms and for a wir e diameter of 0.2 E cm (# 10 wi r e).
Fig. 3-9 Var iati on i n combine resistance of r ods connected in mul ti ple when ar range on a str aight l in e
or a circle with spacing between rods equal to length of rods. Dashed line indicates combined
r esistance with out mu tual ef f ects. Rod length 240 times r od radi us as f or 5 ft . r ods of ½ i nches
diameter.
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D. Treat the soil when 3.4.4 A or 3.4.4 B is not feasible. This is not a permanent way to improve the
ground resistance.
Fig. 3-10 Tr ench method of soil tr eatment
3.5 MAINTENANCE
It is not enough to check the ground resistance only at the time of installation. A continuous, periodic
ground resistance testing should be adopted.
3.5.1 Grounding system requirements from year to year can change depending on the following factors:
A.A plant or facility can expand in size or change its operation and such changes create different
needs in the grounding system.
B. As more non-metallic pipes and conduits are installed underground, such installation becomes
less and less dependable as effective low ground connections.
C. In many locations, the water table is gradually failing, and grounds formerly effective may end
up ineffective.
3.5.2 Ground resistance shall be tested when installed and periodically afterwards, at least once a year
during the dry or non-rainy months and ALL VALUES OBTAINED SHALL BE NO GREATER THAN
REQUIRED IN RULE 3.2.4. B.
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3.5.3 All grounds connections, be it solderless or soldered, shall be checked at least once each year to be
sure they are tight. Physical damage to ground wires shall be checked at the same time and damages
rectified or damaged conductors replaced.
3.5.4 DO NOT TEST GROUNDS DURING THUNDERSTORM DAYS.
3.5.5 Never take hold of two wires or a wire or rod or probe in such a way that should complete a circuit
through yourself.
3.5.6 Stray earth currents, accidental contacts or ground faults in the power system may produce an
undeterminable difference of potential between two points, so use rubber gloves and handle ground wires
under test as if they are energized.
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IV. GENERAL STRENGTH REQUIREMENTS
4.1 GENERAL
4.2 LOADING ZONES
4.2.1 Heavy Loading Zone
4.2.2 Medium Loading Zone
4.2.3 Light Loading Zone
4.3 SAFETY FACTORS
4.4 TRANSVERSE STRENGTH
4.5 VERTICAL STRENGTH
4.6 LONGITTUDINAL STRENGTH REQUIREMENTS
4.6.1 Reduction in Stress
4.6.2 Use of Guys and Braces
4.6.3 Unbalance Loads
4.7 ULTIMATE STRENGTH OF MATERIALS
4.7.1 Wood
4.7.2 Structural Steel
4.7.3 Reinforce Concrete
4.7.4 Conductors, Span Wires, Guys, Messengers
4.7.5 Tower or Pole Foundations and Footings
4.8 DETAILED STRENGTH REQUIREMENTS
4.8.1 Poles, Towers and Other Structures
4.8.2 Crossarms
4.8.3 Pins and Conductors
4.8.4 Conductors
4.8.5 Insulators
4.8.6 Guys and Anchors
4.8.7 Messenger and Span Wires
4.8.8 Hardware.
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SECTION IV
GENERAL STRENGTH REQUIREMENTS
4.1 GENERAL
The Section established provisions covering mechanical strength requirements used in conjunction
with electronic equipment or systems either alone or when involved with electrical power systems. The
provisions of this Section are supplemented in many instances by provisions in other sections.
The rules in this Code complement applicable provisions in the Building Code of the Philippines and
the Philippine Electrical Code. The more restrictive or stringent rules shall prevail.
4.2 LOADING ZONE
The following conditions of the temperature and loading shall be used for the purpose of this Code in
determining the strength required by poles, towers, structures, and all parts thereof as well as in
determining the strength and clearances of conductors. More stringent conditions may be used if desired.
4.2.1. H eavy Loading Zone
A. Heavy loading shall apply to those parts of the Republic of the Philippines as shown in Fig. 4-1.
This loading shall be taken as the resultant stress due to wind and dead weight for 240 kilometer per
hour (kph) wind velocity.
a) Wind pressure on protect area on cylindrical surfaces shall be computed as being 60% of that
for flat surface.
Where lattice structures are used, the actual exposed area of one lateral face shall be increased
by 50% to allow for pressure on the opposite face, provided by this computation does not indicate a
greater pressure than would occur on a solid structure of the same outside dimensions, under which
conditions, the latter shall be taken.
b) Temperature shall be considered to be 27°C at the time of maximum loading. The maximum
temperature shall be assumed as 65°C in computing sag under this condition.
B. Medium loading shall apply to those parts of the Republic of the Philippines as shown in
Fig. 4-1. This loading shall be takes as the resultant stress due to wind for 200 KMP wind velocity and
dead weight under the following conditions:
a)Wind pressure on project area on cylindrical surface shall be computed as being 60% of that
for flat surface.
When latticed structures are used, the actual exposed area of one lateral surface shall be
increased 50% to allow for pressure
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Fig. 4-1Wind L oading M ap
35
THE PHILIPPINE ELECTRONICS CODE
on the opposite face, provided this computation does not indicate a greater pressure than would
occur on a solid structure of the same outside dimensions, under which conditions, the latter shall
be taken.
b) Temperature shall be considered to be 27°C at the time of maximum loading. The maximum
temperature shall be assumed as 65°C in computing sag under this condition.
C. Light loading shall apply to those parts of the Republic of the Philippines as shown in Fig. 4-1.
This loading shall be taken as the resultant stress due to wind for 160 KHP wind velocity and dead
weight under the following conditions:
a) Wind pressure on protected area on cylindrical surface shall be computed as being 60% of
that for flat surface.
When latticed structures are used, the actual exposed area of one lateral surface shall be
increased 50% to allow for pressure on the opposite face, provided this computation does not
indicate a greater pressure than would occur on a solid structure of the same outside dimensions,
under which condition, the latter shall be taken.
b) Temperature shall be considered to be 27°C at the time of maximum loading. The maximum
temperature shall be assumed as 65°C in computing sag under this condition.
4.3 SAFETY FACTORS
4.3.1 The safety factors specified in these rules are the maximum allowable ratios of ultimate strengths of
materials to the maximum working stress, except that:
A. The safety factors for structural steel (towers, poles, cross-arms, supports) shall be applied as
specified in Rule 4.7.2 and
B. The safety factors for wood members in bending shall be applied to longitudinal tension and
compression as ratios of the module of rupture to the maximum working stress. The maximum working
stresses used with these safety factors shall be the maximum stresses which would be developed in the
materials under the construction arrangement with temperature and loadings as specified in Rule 4.2.
4.3.2 Lines and elements of lines, upon installation or reconstruction shall provide, as a minimum, the
safety factors specified in Table 4-1 for vertical loads and load transverse to lines and for loads
longitudinal to lines except where longitudinal loads as balanced.
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THE PHILIPPINE ELECTRONICS CODE
Table 4-1
MINIMUM SAFETY FACTOR
El ements of Constr ucti on
Saf ety F actors
1. Conductors, splices and conductor
Fastenings (other than tie wires)
2. Pins
3. Pole line hardware
4. Line insulators (mechanical)
5. Guy Insulators (mechanical)
Interlocking
Non-interlocking
6. Guys except in lights loading zone
7. Guys in light loading zone
8. Messengers and span wires
9. Wooden poles
10. Structural or tabular steel poles, towers,
cross-arms and steel members of foundation
11. Foundations against uplift
12. Foundations against depression
13. Reinforced concrete poles
14. Cross-arm Wood
2
2
2
3
2
3
3
2
2
4
2
2
3
4
2
4.3.3. Replacement
Lines or parts thereof shall be replaced or reinforced before safety factors have been reduce (due to
deterioration or changes on construction arrangement or other conditions subsequent to installation) to
less than 2/3 of the construction safety factors specified in Rule 4.3.2. In no case shall be application of
this be held to permit the use of structures or any member of any structure with a safety factor less than
unity.
4.4 TRANSVERSE STRENGTH REQUIREMENT
In computing the transverse strength requirements of all parts of structures and in calculating
allowable stresses and allowable minimum sags for conductors under the temperature and loading
conditions specified in Rule 4.2, safety factors at least equal to those of Table 4-1 shall be used. In heavy
loading areas for supporting structures carrying more than 10 wires (not including cables and supporting
messenger wires) when the pin spacing does not exceed 40 cm the transverse wind load shall be
calculated on two-thirds of the total number of such wires with a minimum ten. In cases where, due to
change of direction in conductors, an unbalance side stress is imposed on the supporting structure, a
transverse load shall be assumed equal to the resultant of all conductor tensions under the assumed
loading conditions.
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THE PHILIPPINE ELECTRONICS CODE
4.4.1 Special Pr ovisions
Where it is impossible to obtain the required transverse strength except by the use of side guys or
special structures and it is physically impossible to install them at the location of the transversely weak
support, the strength may be supplied by side guying the line at each side of, and as near as practicable to,
such weak support with a distance not in excess of 245 m. between the supports guyed; provided that the
section of the line between the transversely weak structures is weak in regard, to transverse loads only,
that it is in a straight line and that the strength of the side guyed supports is calculated on the transverse
loading of the entire section of line between them.
4.5 VERTICAL STRENGTH REQUIREMENTS
In computing vertical strength requirements, the loads upon poles, towers, foundations, cross-arms,
pins, insulators, and conductor fastenings shall be their own weight plus the superimposed weight which
they support, including that of wires and cables under the loading conditions of Rule 4.2 plus that which
may be added by difference in elevation of supports. The resultant of vertical and transverse loadings on
conductor shall be used in determining the allowable and working tensions or sags in accordance with
Rule 4.2. In addition, a vertical load of 90 kg. at the outer pin shall be included in computing the vertical
loads on all cross-arms. All members of structures shall be constructed to withstand vertical loads as
specified above the safety factors at least equal to those specified in Rule 4.3.2.
4.6 LONGITUDINAL STRENGTH REQUIREMENTS
In computing the longitudinal strength requirements of structures, or any parts thereof, the pull of the
conductors shall be considered as that due to the maximum working tension in them under the loading
conditions specified in Rule 4.2.
4.6.1 Reducti on i n Stress
Stresses in supporting structures due to longitudinal load may be reduced by increasing the conductor
sags, provided that prescribed conductor clearances in Section VII are maintained.
4.6.2 Use of Guys and Br aces
The longitudinal strength requirements for poles, towers, and other supporting structures shall be met
either by the structure alone with the aid guys or braces. Deflection shall be limited by guys or braces
where such structures alone, although providing the strength and safety factors required, would deflect
sufficiently under the prescribed loadings to reduce clearances below the required values.
4.6.3 Un balance Loads
Poles, towers, or structures with longitudinal loads not normally balanced (as the dead ends or angles
greater that can be treated as in Rule 4.4) shall be sufficient strength or shall be guyed or braced, to
withstand the total unbalanced load with the safety factors at least equal to those specified in Rule 4.3.
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4.6.4 Longitudinal load on each end support of crossings, conflicts or joint use, shall be taken as the
unbalanced load equal to the tension of one-third of the total number of conductors that produces the
maximum stress in the supports. If the application of the above results in the fractional part of a
conductor, the nearest whole number of conductors shall be used. The construction of the supports
(including poles, structures, towers, cross-arms, pins, insulators, conducting, fastenings, and guys) shall
be such as to withstand at all times the load specified with a safety factor at least equal to 2/3 of the safety
factors in Rule 4.3.2.
4.7 ULTIMATE STRENGTH OF MATERIALS
Values used for the ultimate strength of materials in connection with the safety factors specified in
Rule 4.3 shall not be more than as follow:
4.7.1. Wood
Values used for moduli of rupture, for wood in bending in conjunction with the safety factors given in
Rule 4.3 shall not exceed those shown in Table 4-2.
Table- 4-2
WOOD STRENGTHS
Species
M odulus of Ruptur e in Bendin g
6.4 Kg/mm2
1. Apitong
2. Bagtikan
3. Maungachapui
4. Almon
5. Benguet pine
6. Lanipan
7. Pahutan
8. Palosapis
9. Red Lauan
10. Tanguili
do 
do 
5.2 Kg/mm2
do 
do 
do 
do 
do 
do 
Figures are for selected structure grade of material under short time loading with the neutral plane
parallel to a side. Multiply the values by 1.4 where the neutral plane is on the diagonal of a square.
Multiply the given values by 0.55 when the loading being considered is a long time loading (continuous
load for a year or more). Poles shall be given suitable preservation treatment.
4.7.2 Structural Steel
Steel structures, steel structural members and their connections, shall be designed and constructed so
that the structures and parts thereof shall not fail or be seriously distorted at any load less than the
maximum working loads (developed under the construction arrangement with loadings specified in Rule
4.2) ; multiplied by the safety factors specified in Rule 4.3. The safety factors specified in Rule 4.3 shall
be applied as follows to structural steel:
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Tension and Bending: The yield point, 23.2 Kg/mm 2 shall be divided by the safety factor to determine
the maximum allowable working stress.
Compression: The Maximum allowable working stress shall be calculated by the following formula:
 

 

 


Where Smax = maximum allowable working stress in Kg/mm 2
fs = safety factor specified in Rule 4.3
2
YP = Yield point of the steel. 23.2 Kg/mm
1 = unsupported length of a member
r = radius of gyration of a member.
Shear: The ultimate tensile strength, 3.876 Kg/cm 2 shall be multiplied by 2/3 and divided by the
safety factors specified in Rule 4.3 to determine the maximum allowable working stress.
Where the figures given are used, structural steel shall conform to ASTM A7-39 for carbon steel of
structural quality. Other values may be used for steel of other strength provided the yield point and
ultimate tensile are determined by test.
4.7.3 Rei nf orced Concrete
Values used for ultimate strengths of reinforced concrete in conjunction with safety factors given in
Rule 4.3 shall not exceed the following:
Reinforcing steel, tensile or compression strength in Kg/cm 2 3867
Concrete, 1:2:3
Age
7 days
30 days
90 days
6 months
Compressi on Strength
63.5 Kg/cm2
169.00 Kg/cm2
218.00 Kg/cm2
310.00 Kg/cm2
If reinforced concrete is designed for higher strength values which are proven by test, such values may be
used in lieu of the figure given.
4.7.4 Condu ctor s, Span Wir es, Guys, Messengers
Values used for ultimate strength of wires and cables shall not exceed those given in Tables 10 to 14
in the Appendix. For use of types of wires and cables of other materials or composition not included in
the Appendix, values for ultimate strength similarly derived from specifications of the ASTM shall be
used except that, if such specifications are non- existent, manufacturer‟s specifications may be used
provided that test have been made which shall justify the manufacturer‟s rating for ultimate strength.
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4.7.5Tower or pole foundations and footings
In calculating the resistance of foundations or footings of towers, poles and pole line structures to
uplifts, the weight of concrete shall be taken as not more than 2322.6 Kg/mm 3 the weight of earth
(calculated 30 degrees from the vertical) shall be taken as not more than 1441.6 Kg/mm 3. The resistance
of soil to the depression of foundations shall be calculated from the best available data on the soil in
question. In lieu of calculation, the strength of foundations or footings against uplift or depression may be
determined by test under the soil conditions obtaining.
4.8 DETAILED STRENGTH REQUIREMENTS
4.8.1 Poles, Tower s and Other Str uctu r es
A. Strength
Wood poles shall be sound timber, free from defects which would materially reduce their strength
or durability and they shall have sufficient strength to withstand, with safety factors not less than those
specified in Rule 4.3, the maximum stresses to which they are subjected under the loading conditions
specified in Rule 4.2. The modulus of rupture used in calculation and safety factors shall be not greater
than the value given in Rule 4.7.1.
Steel and reinforce concrete poles, together with their foundations, shall be such material and
dimensions as to withstand, with safety factors not less than those specified in Rule 4.3, the maximum
stress to which they are subjected under the loading conditions specified in Rule 4.2. The fiber stress
values used in calculation of safety factors shall be specified in Rules 4.7.2 and 4.7.3.
Certain poles are subject to special stress due to angles in the line, dead ending of conductors, or
other attachments, which stresses must be included in computing the loading and safety factor. Poles
subject to these special stresses sometimes require the use of guys, in which case the pole below the
point of guy attachment shall be considered merely as a strut, the guy taking all lateral stresses. In such
cases, the pole strength requirements shall apply at the point of guy attachment rather than at the ground
line. Spliced or stub reinforced poles or pole top extensions, including the attachments (joints) of
different members involved, shall meet all of the vertical, transverse and longitudinal strength
requirements of these rules as if a whole pole were used.
B.Setti ng of Wood Poles
The depth of pole setting given in Table 4-3 are applicable to wood poles set in firm soil or in solid rock.
Where the soil is not firm, deeper settings or special methods of pole shall be resorted to. Where unguyed
poles are set subject to heavy strain, or at corners or curves, a greater depth shall be used. Guyed poles
may be set more than 0.3 meter less than the depths specified in Table 4-3 provided the guys do not
assume any normal working load under condition of no wind and the resulting depths of setting are not
less than 1 meter.
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Table 4-3
Total L ength
Depth in
Depth in
of Pole, M eter
Soil , M eter
Rock, M eter
6.0
7.5
9.0
10.5
12.0
13.5
15.0
17.0
18.0
20.0
21.0
23.0
24.5
1.2
1.4
1.5
1.5
1.7
1.8
2.0
2.0
2.0
2.3
2.3
2.5
2.5
1.0
1.0
1.0
1.0
1.0
1.2
1.2
1.4
1.4
1.5
1.5
1.7
1.8
C. Gains
Gains or equivalent means may be provided for increasing surface contact of cross-arms with sound
wood poles. Where gains are cut, the depth shall be not less than .5 mm. or more than 5 mm. “Slab”
gains, metal gains, pole bands, or assemblies of wood or metal supports that provide suitable surface
contact and adequate strength are permitted.
4.8.2 Cross-arms
A. Material
a. Wood  shall be of suitable grades listed in Table -2 or other accepted species.
b. Metal  shall be structural steel, cast steel, or malleable cast iron, properly galvanized or
otherwise protected to resist corrosion, or may be of any corrosion-resisting metal or alloy.
B. M in im um Str ess
a. Wood  shall have a cross section not less than .5  .5cm except that cross-arm 2 meter
or less in length may be 7 × 9.5 cm.
b.Metal  the physical properties as a result of dimensions, shape and cross-sectional area of
metal cross-arms shall be such as to result in sufficient strength to meet the requirements of Rules
4.5, 4.6, 4.7.2 provided the thickness of any element shall be not less than 0.23 cm.
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C.Strength
Cross-arms shall be securely supported by bracing, where necessary to withstand unbalance vertical
loads and to prevent tipping of any arm sufficiently to decrease clearances below the values specified in
Section 7. Such bracing shall be securely attached to poles and cross-arms. Supports in lieu of crossarms shall have means of resisting rotation in a vertical plane about their attachment to poles or shall be
supported by braces as required for cross-arms. Metal braces or attachments shall meet the requirements
of Rule 4.7.2 and 4.8.8. In computing the strength requirements to meet vertical loads, the effect of such
bracing may be considered.
(1)Where longitudinal loads are normally balanced, cross-arms supporting conductors shall have
sufficient strength to withstand a load, applied in the direction of the conductors at the outer pin
position of 180 kg. with a safety factor of not less than unity.
(2)Where cross-arms are subjectedto unbalanced longitudinal loads they shall have sufficient
strength to meet the strength requirements with safety factors at least equal to those specified in
Rule 4.3. At unbalanced corners and dead ends, where conductors are supported on pins and
insulators, double cross-arms shall be used to permit conductor fastenings at two insulators and thus
retard slipping.
D. Replacements(See Rule 4.3.3).
4.8.3 Pi ns and Conductor s F astenin gs
A. Material
1. Pins  Insulator pins shall be of galvanized iron or other corrosion-resisting metal or of other
suitable material
2. Fastenings  Conductor fastenings shall be of galvanized steel, galvanized iron or other
corrosion-resisting metal.
B.Size
1. Wood Pins  The minimum diameter of the shank shall not be less than 0mm .
2. Metal Pins
 The minimum diameter of the shank shall not be less than .5 mm.
3. Fastenings and Tie Wires  Fastenings and tie wires shall have not sharp edges at points of
contact with conductors, and shall be applied in such a manner so as not to damage the conductor.
The materials and minimum sizes of tie wires for the various sizes and types of conductor shall be
shown in Table 4-4. Flat wire having a cross-sectional area not less than that of round wire of the
gauge specified for tie wires may be used.
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Table 4-4
SIZE AND MATERIAL OF TIE WIRE
L in e Conductor
M ater i als
Ti e Wir e
Size
Size
M ater ial s
Copper, bronze
Copper-covered
steel or composites
of any of
them
6AWG
smaller
4AWG
2AWG or
larger
Same as line
conductor
6AWG
4AWG
Soft copper or
annealed coppercovered steel
Galvanized iron or
galvanized steel
10BWG and
smaller
9BWG
8BWG
4 & 6BWG
Sames as line
conductor
10BWG
9BWG
8BWG
Soft galvanized
iron or galvanized
steel
Aluminum or
ACSR
4AWG
smaller
2AWG or
larger
Same as line
conductor
4AWG
Soft aluminum
 do 
C. Strength
Insulator pins and conductor fastenings shall be able to withstand the loads which they may be
subjected to with safety factors at least equal to those specified in Rule 4.3.
1. Longitudinal loads normally balanced:
a) Insulator Pins  Where longitudinal loads are normally balanced, insulator pins which
support conductors shall have sufficient strength to withstand, with a safety factor of not less
than unity, a load at the conductor position of 180 kg.
b) Conductor fastenings  Where longitudinal loads are normally balanced, the tie wires or
other conductor fastenings shall be installed is such a manner that they will securely hold the
line conductor to the supporting insulators and will withstand without slipping of the conductor,
unbalanced pulls of 15% of the maximum working tensions but not more than 120 kg.
2. Longitudinal loads normally unbalanced  At unbalanced corners and dead ends where the
conductor tensions are held by cantilever strength in pin-type insulators and pins, double pins and
insulators shall be used and each line conductor shall be tied or fastened to both insulators so as to
prevent slipping of the conductor under the maximum working tensions with a safety factor of 2
under the temperature and loading conditions specified in Rule 4.2.
D. Replacements(see Rule 4.3.3).
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4.8.4 Conductors
A. Material
Conductors shall be of copper, copper-covered steel, bronze, stranded cable composites of any of
the foregoing, aluminum, aluminum cable steel reinforced, galvanized iron, galvanized steel or of other
corrosion-resisting metal not subject to rapid deterioration.
B. Size
Size of conductors for various types of construction and service is specified in Selection 5 & 7.
C. Strength
1. Conductor shall have sufficient strength to withstand, with safety factors not less than those
specified in Rule 4.3, the maximum stresses to which they are subjected under the loading
conditions specified in Rule 4.2.
2. Sags and Tensions  Conductor sags shall be such that in loading conditions specified in
Rule 4.2 the tension in the conductor shall not be more than one-half the breaking strength of the
conductor. The use of sags greater than the allowable minimum may be desirable in order to reduce
working tensions.
3. Splices  Splices in conductors shall be in accordance with the requirements of Table 4-1
except as provided in Rule 4.7.4.
4. Service drops for telephone, data, etc. of No. 16 AWG paired copper wire maybe used,
provided they do not cross over power lines, trolly contact or feeder conductors of railways and the
like. Paired high strength service drops of No. 18 AWG high strength bronze or high strength
copper-covered steel may be used provided the breaking strength of the pair is not less than 155 Kg.
D.Replacements (see Rule 4.3.3).
4.8.5 I nsulators
A. Line
Insulators, supports, clamps, and other miscellaneous attachments shall be designed to
withstand, with at least the safety factors specified in Rule 4.3, the mechanical stress to which they
are subjected by conductors, wires or structures, under the loading conditions specified in Rule 4.2.
Pin insulators shall effectively engage the thread of the pin for at least two and one-half turns.
B. Guy
Guy insulators, including insulators in messengers, shall have mechanical strength at least equal
to that required of the guys in which they are installed.
C. Replacements (see Rule 4.3.3).
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4.8.6 Guys and An chor s
A. Material
The exposed surface of all guys and guy rods shall be of corrosion-resisting material.
B. Size
The size and strength of guys shall be not less than as specified in Table 4-5 and shall also be such
as to provided safety factors not less than those specified in Rule 4.3, for the loads imposed by the
construction under the loading conditions specified in Rule 4.2.
Table 4-5
MINIMUM SIZE AND STRENGTH OF GUYS
M ini mum Size
M ateri al of Str and
An chor, Guys
1. Galvanized Steel
Common or Siemens
Martin
High Strength or
Extra High Strength
2. Copper-covered Steel
3. Bronze
Minimum Allowable
Ultimate Strength
of Guys
Overhead Guys
8 mm
6.5
6.5 m
5m
3 No. 9AWG
6.5 mm
1454.54 Kg.
(3200 lbs.)
3 No. 10AWG
3 No. 10AWG
863.63 Kg.
(1900 lbs.)
C. Strength
When guys are used with poles or similar structures, capable of considerable deflection before
failure, they shall be able to support the entire load, the pole below the point of guy attachments acting
merely as a strut. Stranded wires shall be used when the ultimate strength of the guy exceeds 820 Kg.
Anchor rods and their appurtenances shall meet the same strength requirements as the guy wire or
strand (see Rule 4.3)
D. Replacements(see Rule 4.3.3).
4.8.7 M essengers and Span W ir es
A. Material
Messengers and span wires shall be stranded of galvanized steel, copper-covered steer or other
corrosion-resisting material not subject to rapid deterioration.
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B. Strength
Messengers and span wires shall be capable of withstanding, with safety factors as specified in Rule
4.3.; the tension developed because of the load they support combined with the loading conditions
specified in Rule 4.2. An allowance of 90 Kg. of vertical load for a man and cable chair shall be made
in computing tensions in messengers and span wires which supports cable except in the case of short
spans which are not required to support workman. The strength of guys supporting messenger loads
shall be such that the safety factor of such guys is not less than the safety factor required of the
messenger as specified in Rule 4.3. It is recommended that overhead guys shall be the same size as the
suspension strand to compensate for the angle between the plane of the horizontal load of the
suspension strand and the line of the guys.
C. Supports
Messenger supporting cables shall be attached to poles or cross-arms with hardware which provides
safety factors at least equal to those specified in Rule 4.3, based on the weight of the cable plus an
allowance of 90 kg. for the man and cable hair. All hardwares subject to injurious corrosion shall be
protected by galvanizing, or other suitable treatment.
D. Replacements (see Rule 4.3.3).
4.8.8 Hardware
All pole line hardware shall be galvanized, otherwise protected by a corrosion-resisting treatment,
or shall be composed of material which is corrosion resistant.
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V. INDOOR PLANT SAFETY RULES
5.1 GENERAL RULES
5.2 RADIO TRANSMITTING & RECEIVING INSTALLATION
SAFETY REQUIREMENTS
5.2.1 Fixed Station Installation
5.2.2 Mobile Station Installation
5.3 SWITCHING EQUIPMENT INSTALLATION SAFETY
REQUIREMENTS
5.4 COMPUTER AND DATA INSTALLATION SAFETY
REQUIREMENTS
5.5 STATION INSTALLATION SAFETY REQUIREMENTS
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SECTION V
INDOOR PLANT SAFETY RULES
5.1 GENERAL RULE
This Section establishes safety rules for all electronics and communications equipment installed
and/or located inside buildings or in sheltered structures, except consumer products.
5.1.1 All electronics and communications equipment except consumer products installed and/or located
inside buildings or in sheltered structures shall be engineered, installed, operated and maintained in such a
manner that SHOCK CASUALTY or FIRE HAZARD shall not result when normally used and operated.
5.1.2 A grounding system shall form a part of all indoor electronics and communication installations
falling under any of the following category:
A. When any equipment is powered from 110 V. A.C. or higher;
B. When an outdoor “exposed” facility is connected to any equipment for its normal operation;
C. All radio stations, telephone/telegraph/telex exchanges and fixed computer installations.
5.1.3 The grounding system shall be designed to direct foreign potentials and surge currents in the
shortest route possible to earth.
5.1.4 Potential rise on accessible parts shall be no greater than the values specified in rule 3.1.5 C.
5.1.5 Strength consideration for indoor equipment installation shall be sufficient to assure that no casualty
hazard shall result from falling or collapsing equipment or their components.
5.1.6 Operation of electronic and communications equipment shall not result in emission of fumes,
chemicals, radiations, etc. to such a level considered hazardous by those recognized by the government to
make such assessment.
5.1.7 Users of electronics and communication system or services shall be protected from shock or fire
hazards attendant to the use of the service.
5.1.8 It shall be the user‟s responsibility to ascertain that adequate internal protection is built into the
equipment by the supplier in such a manner that no shock or fire hazard shall result when the equipment
is operated within its rating.
5.1.9 The electrical protection measures shall coordinate with the inherent dielectric strength and surge
current carrying capacity of the equipment or system being protected.
5.1.10 Only approved protectors and other electrical surge protection devices shall be used.
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5.1.11 The amount of protection for the equipment to be designed into the system is dictated by the value
of service continuity and repair cost attributed to damages in the absence of the protection measure
against the cost of installing and maintaining the protection measures. Safeguarding of persons shall be
the foremost factor in the design and consideration of protection measures.
5.1.12 Fuel tanks shall not be located between antenna towers and the radio building.
5.1.13 The building ground ring conductor shall be buried not less than 0.3 meters below grade level and
between 0.3 and 0.5 meters from the foundation. The building ground rods shall be spaced not more than
6.0 meters apart around the building.
5.1.14 Where ground wires cross each other, they shall be bonded together to prevent arcing.
5.1.15 Points with potential in excess of that specified in rule 3.1.5 as hazardous voltages may be made
accessible as may be required for testing/maintenance purposes by removal of shields or barriers so
marked indicating that its removal will expose hazardous voltage. The voltage of the part to be exposed
shall be indicated in the same marking with further instruction to return the shields or barriers after the
work.
5.1.16 When working on points specified in Rule 5.1.15, extreme caution shall be exercised and the
following observed:
A. Use tools with insulated handles;
B. Place rubber mats or equivalent on the floor where the persons required to access such points
may stand on;
C. Only authorized, competent persons shall be allowed to undertake work that may expose them
to such hazardous voltages.
D. No person shall undertake such work alone.
5.1.17 Circuits and components capable of retaining an electrical charge after the power to the equipment
is turned off causing a discharge of 50 watt-seconds of energy or more through a 1500 ohms resistor
connected across its terminals, shall be fitted with circuitry to drain or remove this charge when the
equipment power is turned off.
5.1.18 Stationary battery installation mounted on racks shall be fitted with earthquake bracings
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Notes to Table 5-1
Item
DESCRIPTION
1
The building or tower ground ring are conductors attached to ground rods forming a ring around
the building or tower which are in direct contact with the soil and form the primary earth
electrode.
2
It is good practice to bond the building structural and metal framework to the building ground
ring. New radio buildings should have electrically continuous structural metal framework or
reinforcement accessible at some points for bonding to ground.
3
When ground ring is the primary earth electrode, it shall be wired to the main ground bus for
distribution. Other made grounds specified in rule 3.2.4 C may be used place of the ground ring
or combinations of various made grounds to attain the requirements of rule 5.2.1 E.
4
When available the public metallic underground cold water pipe system with at least 3.0 meters
of metal pipe in direct contact with the earth, shall be bonded to the main ground bus.
5
The tower ground ring shall be bonded to the building ground ring or to whichever made ground
is used.
6
Tower radial grounding conductors uses and applications are described in rule 8.4.1 F.
7
Each tower leg of self-supporting towers or the base or footing of guyed towers shall be bonded
from two points on the tower grounding plate to the tower ground ring.
8
Guy wires shall be bonded to the guy earth electrode or guy ground ring whichever is used.
Ground ring configuration of three ground rods driven in a triangular pattern around guy anchors
interconnected to each other using No. 2 AWG bare copper wire.
9
The fuel tank metal structure if present shall be bonded to building ground ring.
10
This is the grounding conductor installed the full length of the pole or tower, free at the top end
and bonded at the bottom to the tower grounding plate and to the tower earth electrode or ground
ring.
11
The lightning rod or protective device installed at the topmost of the tower or pole shall be
bonded to the tower grounding conductor.
12
All ground elements of antenna, antenna supports, waveguides, shields or coaxial cables and
tower lightning metal conduit shall be bonded to the grounding conductor to assure good
electrical continuity to ground.
13
Metal structures or runways supporting waveguides coaxial cables, etc. from the tower to the
building shall be bonded to ground.
14
The main ground bar is a copper bar serving as the principal terminating point installed on the
lowest floor level of the building (basement or first floor).
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THE PHILIPPINE ELECTRONICS CODE
15
This grounding conductor run is form the main ground bar to the equipment rack lineup. This
conductor is normally made to run cable runways atop equipment rack lineup where individual
equipment rack and rack ground wires are bonded to.
16
For equipment racks, grounding conductors are fitted running the length of the rack to facilitate
neat individual equipment shelves grounding.
17
See No. 16
5.2 RADIO TRANSMITTING & RECEIVING SAFETY REQUIREMENTS
5.2.1 F ix ed Station

(Point-to-Point; Television, FM & AM, Radio; Space Communication)
This section covers radio transmitting and receiving stations at fixed locations used for point-to-point
overland or space communications and video, AM and FM transmission.
A. A fixed radio station building is not likely to be struck directly by lightning because of the
shielding effect provided by the antenna tower/s or support structures. However, waveguides, the
shield 2 of coaxial cables and high frequency antenna transmission lines can conduct hazardous
currents into the building unless adequate protective measures are employed. The station grounding
system is employed to divert as large a proportion of the surge current directly to earth before it enters
the building. The grounding system shall also be designed to reduce earth potential gradients in and
around the station building.
B.Radio site protection involves special consideration because direct lightning hits are usually
expected. The bonding, grounding and protection schemes shall have to be heavy duty and very
carefully engineered, installed and maintained in order to hold differences of potential between
various parts of the station to safety values. The installation shall be adequately grounded and
incoming overland communication and power lines fitted with special protection devices. The extent
to which protection measures must be carried and their effectiveness is greatly affected by the earth
resistivity at the station location.
C. Equipment protection design is based on preventing voltage surges, beyond the voltage surge
limit of the equipment or parts thereof, from reaching that equipment or component. For solid state
component protection, low voltage protection devices have limited surge capability themselves,
several stages of protection may be employed.
D. Most electronic and communication equipment installations require A.C. power for certain
components. Commercial power lines, being susceptible to voltage and current surges due to
lightning and switching operations, shall necessitate protection considerations to prevent damage to
equipment connected to such lines.
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E. The earth electrode shall be any or a combination of “made electrodes” specified in rule 3.. C.
The ground resistance shall not be greater than 2.0 ohms at all times as measured by the fall of
potential method as specified in rule 3.4.1 B. Conductor size shall be no less than those specified in
Table 5-1. Aluminum, copper covered steel and other types of conductors may be used in place of the
copper conductor specified in Table 5-1 provided the current-carrying, corrosion-resisting
characteristics and insulation are equal to or better than the specification of the conductor being
replaced. The minimum wire size specified in Table 5-1 is for electrical protection consideration only
if the system design calls for portions of the grounding system network to carry operating currents,
the conductor size shall be increased correspondingly.
5.2.2 M obil e Station  (Land mobile; Maritime mobile; Aeromobile)
This section covers radio transmitters, receiver, transceivers and allied equipment at mobile locations
such as:
1.   radio installation on board vehicles, like automobiles, trucks, trains, etc. whose
movement or travel in confined overland.
2.   radio installation on board water crafts like boats, ships, etc.
3.Aeromobile  radio installations on board aircrafts and space crafts.
A. The counterpart base station of such mobile installations shall comply with safety provisions
provided under Rule 5.2.1
B. Installation of transceivers, handsets, control panels, microphones, loudspeakers, etc. shall not
increase the risk of injury of the driver or pilot and passengers in case of accident or collision.
C. Battery cables shall be fused as close to the battery terminals as practicable with fuse rating not
greater than 150% of the peak load current.
D. Battery cables shall have a current carrying capacity of not less than 250% of the peak load
current.
E. Battery cables shall have insulation strength rating of not less than 10 times the maximum
voltage to which it is to be connected and adequate mechanical strength to withstand the expected
abrasion; exposure to dirt, heat (150 °C), humidity and the extreme environmental conditions mobile
installations encounter.
F. Battery or power wiring in aircraft installations shall be adequately fused in such manner that
current overloads due to equipment or wiring malfunction shall not affect other vital navigation
equipment in the aircraft connected to the same battery or power supply.
G.Electronic and communication installations in larger water craft or trains are mostly powered
from normal A.C. supply and in such cases, rules in this Code to meet general rule 5.1.1 apply.
H. Cables to be used for watercraft installation shall be those approved for marine application.
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      (Telephone, Telegraph, Telex etc.)
This section covers equipment installation employed for selective interconnection of channels of
communication using electro mechanical and/or electronic circuit elements to perform the function.
5.3.1Switching equipment is subject to damage from lightning and power fault currents which may be
conducted from outside plant cable or wire circuits. A.C. operated equipment can be damage from
lightning and switching surges conducted through the electric power lines. To protect personnel and
prevent damage to equipment these foreign potential surges shall be effectively limited by application of
suitable protective devices.
5.3.2 Surge arresters of suitable type and rating shall be connected on all wire circuits entering the
building except on wire lines meeting all of the following criteria:
1. The entire length is underground;
2. Not bunched with a circuit any portion of which is installed above ground level;
3. Not bridged to any wire circuit that may be exposed to foreign potential by contact or induction.
5.3.3 Depending on the desired protection level adopted, arresters should be fitted on power services
serving the station.
5.3.4 The switching office earth electrode shall be any or a combination of “made electrode” specified in
Rule 3.2.4 C. The ground resistance shall be 5.0 ohms or less at all times as measured by the fall of
potential method.
5.3.5 The earth electrode(s) provided under the rule 5.3.4 shall be bonded to the following (when present)
to form the switching office earth electrodes:
1. Continues buried metallic public water pipe system;
2. Continues buried metallic private water pipe system with at least 3.0 meters of buried pipe;
3. Deep well metal casing.
5.3.6 Connections to earth electrodes shall be made using methods and clamps acceptable to the entity
enforcing this CODE.
5.3.7 For big offices, a ground bar shall be used, connected to the earth electrodes. The ground bar serves
as distribution or principal terminating point. For small offices the for ground may be omitted and
grounding conductor connected to the earth electrode on one end, free on the other end and running the
full length of the equipment line-up, where equipment rack/s shall be bonded.
5.3.8 Ground conductor sizes, shall be in accordance with Table 5-1.
5.3.9 Insulation of all cables shall be polyvinyl-chloride (PVC) or equivalent formulation with equal or
better resistance to burning.
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5.3.10 Office furniture‟s required in the operations should be of metal construction or other noncombustible material contents.
5.3.11 Stationary and other office and maintenance supply shall be stored in areas external to the
switching rooms. It shall be prohibited to store combustible materials in transformer vaults, switch gear
rooms and power distribution.
5.4 COMPUTER AND DATA SAFETY REQUIREMENTS
This section covers the minimum safety requirements in Electronic Data Processing Center
installations. Values, in terms of direct monitary cost, as a result of expensive components and in terms of
operational service continuity, tend to be extremely high and expensive damage to these installations can
have catastrophic consequences.
5.4.1 The EDP equipment is AC operated and can be damaged by current surges conducted through the
electrical power line. To protect personnel and prevent damage to equipment, these foreign potential
surges shall be effectively limited by application of suitable protective devices.
The EDP Center earth electrodes shall be any or a combination of “made electrodes” specified in
rule 3.2.4 C and shall be engineered and installed in accordance with rules 5.3.4 through 5.3.8 of this
code.
5.4.2 The Computer is the vital nerve center in any EDP installation and prevention of fire shall be the
overriding concern.
A. The computer shall be provided with physical separation or orientation to reduce or minimize
the effect of any detrimental external influences.
B. The facility shall be installed in a non-combustible housing structure. This shall include fire
and explosion-proof protection from the surroundings,  such as firewalls, smoke detectors, water
proof ceilings, and floor covering materials of Vinyl tiles, high pressure plastic laminates, or other
non-combustible materials.
C. The large quantity of wiring associated with such installation and the mandatory requirements
for air-conditioning leads to concealed spaces either under the floor, in the walls, or in the ceiling.
Obviously, no combustible should be stored in these concealed spaces.
D. Power circuits and signal circuits shall be installed in separate conduits and raceways.\
E. The signal wiring shall be contained in cable structure with an over-all jacket or Polyvinyl
Chloride (PVC) or equivalent formulation with equal or better resistance to burning.
F. Office furniture‟s required in the EDP operations should be of metal construction or other noncombustible material contents.
G. Stationary and other office and maintenance supply shall be stored in areas external to the
computer room. It shall be prohibited to store combustible materials in transformers vaults,
switchgear rooms and power distribution centers.
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5.4.3 The Computer require special environmental conditions such as humidity, temperature and dust,
making air-conditioning system a vital accessory to operation and shall be given equal attention as fire
prevention.
A. The air-conditioning unit shall be installed in a non-combustible area cut-off from all other
areas. If possible the air-conditioning unit for the computer room shall be independent of equipment
supplying the other areas in the building.
B. The rules and regulations of existing codes for the practice of air-conditioning shall prevail.
5.4.4The preservation of data or information on tapes, cards, drums, or disks, is the critical feature of any
computer installation and shall be given careful evaluation. Stored information maybe irreplaceable or can
only be collected by costly and laborious procedures.
5.5 Station Saf ety Requir ements
A station installation for the purpose of this Code shall comprise all equipment installed inside
customer premises such as telephone instruments, teletype/data/CRT terminals, PABX/PBX, etc. either
customer owned or leased requiring a physical line connection to a serving office for its normal operation.
The associated in-house wiring and service drop is considered part of the station installation. Cable TV
and CATV are covered in this section up to the extent of their service drops their protectors and
associated wirings (when required).
5.5.1 Protectors
5.5.1.1 Electrical protection shall be provided for station installation falling under any of the following:
A. The line serving the station is partly or fully of aerial plant installation.
B. The station equipment operates from voltages thru the line in excess of 45 VAC RMS or 135
VDC (telephone ringing voltage not considered).
C. Where the station equipment is installed in a bathroom, near a swimming pool, on a boat dock or
in a boat.
D. Where any loop served by the station equipment is exposed to lightning.
E. Any on-premise extension whose facility could accidentally come into contact with supply
voltages must have protection at both ends.
5.5.1.2 Protectors shall be used on station installations falling under any of the conditions in rule 5.5.1 A
thru E.
5.5.1.3 Protector voltage breakdown rating shall be as low as may be allowed by the circuit being
protected.
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5.5.1.4 Fuseless station protectors may be used when one of the following is satisfied:
A. When a 24 AWG building entrance cable is used with its metal shield grounded to the station
ground at one end at the distribution cable shield (grounded) at the other. This cable may terminate
directly to:
1. on fully enclose fuseless protected terminals;
2. on unprotected terminal blocks with fuseless protectors cross-connected, all fully enclosed;
and,
3. on central office protectors thru an accepted fire retardant terminating cable.
B. When the possibility of foreign potential reaching the customer equipment thru the service and
drop wirings is remote.
C. When there is inserted in the circuit at least 0.5 meter of 24 AWG wire or equivalent between
the customer premises and exposed plant.
5.5.1.5 Fused station protectors shall be used when conditions listed in rule 5.5.1.4 cannot be met.
5.5.1.6 Protectors shall be located as near the drop wire entrance point as possible and the wiring from the
protector to the service entrance point shall not exceed 2 meters.
5.5.1.7 Protector location shall consider the following:
A. Must be accessible for maintenance
B. Avoid excessively damp locations and where the atmosphere may be combustible.
C. At least 15 cm. away from curtains or draperies.
D. At least 30 cm. from electric wires, devices or appliances.
E. Avoid locations subject to tampering or where materials may be stored or placed against it.
F. Must be separated by rigid mechanical divider from supply devices and wirings.
5.5.2 Grounding and B onding
5.5.2.1 Customer equipment installation and wiring shall meet rule 3.1.5.
5.5.2.2 Ground wires run shall not exceed 15 meters of No. 10 or 14 AWG wire, free from sharp bends
and kinks.
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5.5.2.3 Earth grounds shall be selected and used in the following order:
A. A public or private water system metallic pipe buried and in contact with the earth for at least 3
meters.
B. Buried extensive metallic pipes or tanks.
C. Ground rods.
5.5.2.4 Ground connections shall not be made to gas, gasoline, or oil lines, fuel tanks, power transmission
towers, hot water pipes, etc.
5.5.2.5 Ground rods shall not be placed within 2.0 meters of foreign ground rods.
5.5.2.6 Ground resistance shall not exceed the maximum value specified in rule 3.2.4 B.
5.5.2.7 Ground and ground wirings shall consider the following.
A. Ground wiring continuous, free of splice and sharp bends and not subject to tampering.
B. Ground wiring run as short as possible and never exceeding 15 meters of No. 10 or 14 AWG
wire.
C. Do not run ground wires through wooden or similarly combustible material, walls or floors.
D. Not less than 5 cm. from drop or supply wirings.
5.5.3 Location
The station equipment location must be such that any part of the station equipment cannot be reached
or held by a person in the tub or pool, or in the water adjacent to a dock or boat.
5.5.4 Speci al Occupancy
Special protection measures shall be adopted for the following:
A. Power generating and sub-stations.
B. Flammable material processing, storage or loading areas.
C. Mines
D. Trailer trucks
E. Radio tower sites
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5.5.5 Customer Equi pment Safety Requi r ements
Without proper protection, subscriber/customer equipment and telephone subsets, are susceptible to
damage from transient voltages on the telephone line and may cause shock to the users.
This section covers the minimum safety requirements in the instruments/equipments and in the
installations of such customer equip ments in the subscriber‟s premises.
The transient voltages and currents in the telephone lines may be caused by the following:
(1) Lightning strikes
(2) Close proximity of the telephone lines to power lines
(3) Contact with power lines
(4) The normal operation of a telephone subset
5.5.6PBX/PABX
A PBX (Manual Private Exchange) or a PABX (automatic) is a private branch exchange equipment
using a machine, electromagnetic or electronic switching unit to provide inter-communication and outgoing service, but usually equipped with a manual switchboard for receiving and distributing incoming
calls.
A. Proper equipment installations shall be employed in accordance with the rules of Sec. 5.3 of this
Code.
5.5.7 Telephone I nstru ments
A. Adequate protection shall be provided the instrument from:
(1) Transients from lightning strikes
(2) Transients from power lines in close proximity to the telephone lines which may present an
interference problem, but are unlikely to reach the levels of a transient from lightning even for
starting current of heavy machineries.
(3) Transients due to the sudden change of electrical circuit condition, open-circuit line voltage
(44 to 66 volts) caused by lifting of the handset or the ringing of a telephone subset.
B. Proper equipment installations shall be employed in accordance with the rules of section 5.3 of
this Code.
C. Cars have to be taken that protection circuits do not interfere with the normal operation of the
system.
5.5.8 Data and T elegraph Termi nals
These equipment, being AC operated, shall be installed to conform with the rules of Sec. 5.3 of this
Code.
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VI. POWER SOURCES
6.1 GENERAL
6.1.1 Applicability
6.1.2 Considerations
6.2 CONSTRUCTION/PROTECTION REQUIREMENTS
6.2.1 Storage Batteries and Charges
6.2.2 Main or Standby Electric Generators
6.2.3 Others
6.2.4 Power Wiring
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SECTION VI
POWER SOURCES
6.1 GENERAL
Electronic equipment almost always depend on electrical energy for its operation. Electric power
sources availing of electronic technology developments in efforts to support the steadily increasing
industry emphasis on reliability and performance of electr onic system and equipment, have attained a
certain degree sophistication. Consideration of the system and equipment performance is coupled with the
demand for protection  protection of persons and properties from hazards resulting from the operation
and use of power sources for electronic equipment and system in particular.
6.1.1 Applicability
This section established safety provisions on the installations, operation and use of power sources and
devices for electronic equipment and systems.
6.1.2 Considerations
Foreign potentials hazards, strength requirements and environmental hazards due to the operation of
power systems and devices are the primary consideration of this section with performance being touched
only when related to any of the above three considerations.
6.2 CONSTRUCTION/PROTECTION REQUIREMENTS
6.2.1 Storage Batteri es and Char ger s
This section applies to all stationary installation of storage batteries for use with or associated with
equipment used with electronic equipment, devices or system except consumer products.
A. Batteries should be located where temperatures range between 15.5 and 32.2 degrees Celsius
(60° and 90°F). Higher temperatures will shorten battery life and lower temperature will decrease the
ampere-hour capacity and may damage the battery by freezing especially when the batteries are in low
state of charge.
B. Lead acid or similar gas emitting battery installation where the aggregate power (ampere-hour
rating, at the 8-hour rate to 1.75 volts per cell, multiplied by the battery voltage) exceeds 5 kilowatts
shall be located in a properly ventilated room separated from the equipment room or location where
people are staying.
C.Explosion resistant vents shall be provided for all lead acid or similar gas emitting batteries
above 10 ampere-hour capacity and ascertained by periodic inspection that the vents are free from
obstruction.
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D. Ventilation of the battery room is very important especially during high charging and
discharging conditions. Although the battery is fitted with an explosion proof vent, an enclosed room
could develop a sufficiently high concentration of an explosive gaseous mixture which could be ignited
by sparks or open flame introduced by personnel. All air moved by ventilation in the battery room or
area should be exhausted in the outside atmosphere and should not be allowed to recirculate into other
confined areas.
E. Smoking and storing of inflammable materials is prohibited in battery rooms and “NO
SMOKING” signs should be posted in conspicuous locations inside and before entering battery rooms.
F. Batteries, where the corrosive electrolyte may be added in the field or customer location,
transported by air or boat shall be shipped “dry charge”. They may be transported with electrolyte via
land transportation provided electrolyte leakage or spillage are contained with its crate or carton and
proper markings regarding handing precautions are clearly marked on its crate or carton.
G. Batteries on racks shall be provided with earthquake bracings which hold the sides of the
batteries and prevent them from falling off the rack.
H. For noise consideration, grounds may have to be separated as one of the various possible means
to help meet noise objectives and, in such case, the grounds may be insulated from each other except at
the final point of earth connection at the master ground bar or earth electrode.
I. Power cables are sized to limit the voltage drop due to resistance of the cable and hold heating of
the cables to a safe limit. The limits of minimum voltage are critical to the operation of the equipment,
therefore, it is important that voltage drops in the cabling be carefully controlled.
J. The formula for calculating the conductor size is:
Area of Conductor  mm2 = length of load in m. × current in
amperes × 1.81 × 10 -6
allowable drop in volts
Note: for copper wire only
The result obtained shall be checked and increased if necessary to insure meeting the conductor size
requirements of the latest edition of the Philippine Electrical Code.
K. Attempt should be made to limit the overall voltage drop from the battery to the working
equipment to a maximum of one volt. The final selection of cable size should be generous since the
calculation makes no allowance for voltage drop due to items such as fuses, switches, etc.
L. Various battery voltages may be derived by connecting a number of cells in series and in all
cases Rule 3.1.5 D shall not be violated.
M. Frames of battery chargers, battery enclosures if provided, and all exposed metallic structures
shall be bonded together and grounded, meeting Rule 3.1.5 D. and 3.1.5 E.
N. Caustic soda or ether acid neutralizing agents should be stored and available in battery rooms for
use in accidental electrolyte or acid spillage.
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6.2.2 M ain or Standby El ectri c Gener ators
A. Generators may be situated outside the building on a poured concrete slab in which case weather
resistant housing should be provided. The automatic transfer panel (if provided) should be mounted
inside the building.
B. Generators may be located within a power room which may or may not be a part of the building,
housing electronic equipment. This room shall have its own outside door with insulated fire proof
partition wall between the equipment and power room.
C. Incoming fresh air should be brought in through a louvre with a filter and exhaust gases should
be piped to the outside through an approved fire-safe thimble.
D. Generator concrete slabs shall be constructed to meet applicable provisions in the building code
and good engineering practice.
E. Fuel tanks shall not be located between towers and the equipment building.
F. All exposed metallic structure in power rooms including the generator frame or housing shall be
bonded together and grounded, meeting Rules 3.1.5 D. and 3.1.5 E.
G. Electric generators installed and used primarily to power electronic equipment shall meet
provisions of this code and other applicable provisions in the latest issue of the Philippine Electrical
Code.
H. The generator should be protected to prevent equipment damage and its attendant hazards due to
overload temperature rise, over speed, loss of lubricant, etc.
6.2.3 Others
A. Wind driven electric generators or chargers shall be mounted meeting structural strength
specifications for wind velocities prevalent in the zone it is situated.
Provision for “feathering” should be provided to reduce the possibility of damage due to high wind
velocities; automatic “feathering” is desirable.
B. Gas operated (propane, LPG, etc.) thermoelectric generators shall be situated in well ventilated
locations such that fuel leakage shall neither result in the accumulation of a combustible mixture nor
induce harmful effects.
C. In all cases, all exposed metal parts shall be bonded together and grounded, meeting
Rule 3.1.5 D.
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6.2.4 Power Wir ing
A. AC service distribution system in buildings housing electronic equipment or system shall be
solid grounded systems. The basic characteristics of a solid grounded system is that AC secondary
network incorporates a grounding conductor that provides a low impedance bond from one AC service
conductors to ground.
B. For three-phase system, the secondary shall be wye-connected with grounded neutral and for
single-phase system, one conductor shall be at ground potential. The ungrounded conductor shall be
referred to as “current carrying conductor” and the other conductor called “grounded conductor” or
“neutral conductor”.
C. The AC equipment ground system is composed of the raceways or conduits and a network of
insulated conductors. The conductors shall be extended through the conduit or raceways that carry AC
phase conductors, and connected to the non-current carrying framework of the equipment associated
with the AC system. The purpose is to provide a low-impedance path for fault current from a point of
fault to overcurrent protective devices to ensure desired operation in-spite of any inadvertent
discontinuous in raceways or conduits.
D. The neutral or grounded conductor shall not be used as grounding conductor. It is a single-point
grounded, current carrying circuit conductor, grounded on the bus bars of the branch circuit breaker
main service enclosure only.
E. The grounding conductor shall be copper, and shall be installed in accordance with Rule 3.3.4.
F. At the point of connection to the neutral equipment, the grounding conductor shall be bonded to
the metal enclosure and frame in which the service is bond.
G. All conduits, raceways, switch boxes and neutral equipment, cabinets containing current
carrying conductors shall be bonded together and grounded in a manner to assure direct low impedance
paths to ground for surge currents.
H. The branch power circuit for aircraft warning lights should be protected by application of
arresters located at the warning lights fixtures and at the base of antenna mast or tower equipment with
warning lights.
I. Arresters are provided by power companies to protect their distribution transformers against
lightning surges. But their arresters do not provide all the protection needed for building wiring and
load equipment. It is still possible for surges from lightning, line faults or switching operations to enter
communication equipment over the power service entrance conductors. A high degree of protection for
such conditions can be acquired by adding arresters to the secondary power cicuits.
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J. The selection of an arrester for a particular application is determined by six major considerations:
a) the transient voltage breakdown of insulation and of equipment components to be protected;
b) the nominal steady-state voltage of the circuit (live wire to ground) to be protected.
c) the maximum a.c. voltage interrupting rating of the arrester. This is the maximum steady-state
voltage at which the arrester will clear power follow current.
Arresters rated at 175 V/RMS are typically used on 120 volts systems and 260 volts RMS rated
arresters are typically used on 240 volts system.
K. Light duty arresters should be used for protection of branch circuits and for experienced or
anticipated transients not exceeding 5 KA peak current and where the insulation of the protected
equipment can service the transient voltage.
L. Heavy duty arresters should be used for installation requiring a high degree of dependability
under very high transient discharge currents, normally used on high KVA services and heavy feeders.
M. Ground fault protection of equipment may be used which operates by the imbalance of go and
return current in the normal load conductors (phase and neutral wires). This however, is not for
personnel protection.
N. Ground fault protection of personnel which is a circuit breaker with a 5 milliampere ground fault
interrupter should be used on branch circuits serving a.c. convenience outlets for portable appliances,
tools and test equipment. They are mounted in a.c. branch circuit enclosures in central offices in place
of the standard breaker. Ground fault interrupters duplex receptacle for use in place of standard duplex
convenience outlets operating on the same principle as the ground fault interrupter circuit breaker, may
be used for the same purpose.
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VII. OUTDOOR PLANT SAFETY RULES
7.1 GENERAL
7.1.1 Scope of Rules
7.1.2 General Requirements
7.1.2.1
7.1.2.2
7.1.2.3
7.1.2.4
7.1.2.5
7.1.2.6
7.1.2.7
7.1.2.8
Design Construction and Maintenance
Inspection
Avoidance and Conflict
Cooperation to Avoid Conflict
Abandoned Lines
Foreign Attachments
Tree Trimming
Stepping
7.2 GROUNDING AND BONDING
7.2.1 Earth Ground
7.2.2 Bonding
7.2.3 Manholes
7.2.4 Buried Cables
7.2.5 Risers
7.3 JOINT USE OF POLES OR STRUCTURES
7.4 CLEARANCES
7.4.1 General
7.4.2 Above Ground
7.4.3 Above Railways and Trolley Lines
7.4.4 Between Wires, Conductors, Cables & Messengers
7.4.5 From Structures
7.5 CLIMBING SPACE
7.6 VERTICAL RUNS AND RISERS
7.7 GUYS AND ANCHORS
7.8 MISCELLANEOUS EQUIPMENT
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THE PHILIPPINE ELECTRONICS CODE
SECTION VII
OUTDOOR PLANT SAFETY RULES
7.1 GENERAL
7.1.1 Scope of Rul es
This section establishes detailed safety requirements for the outdoor portion of electronic systems and
plants. These rules are supplemented, in certain cases, by rules in other sections of this Code and applies
to systems and plants installed above or below ground level.
7.1.2 Gener al Requi r ements
7.1.2.1 Design, Construction and Maintenance
A. Outdoor electronic plants or systems should be of suitable design and construction for their
intended use, regard being given to the conditions under which they are to be operated. Any portion of
the electronic outdoor plant shall be designed and constructed with sufficient strength to withstand, with
safety factors not less than those specified in Rule 4.3.2, the maximum stresses to which they will be
subjected under the loading conditions specified in Rule 4.2, and shall be maintained in such conditions
as to provide safety factors not less than those specified in Rule 4.3.3.
B. The owners and employees of such system shall at all times exercise due care to reduce to a
minimum the hazard of accidental injury to their own or fellow employees, to the public and other
utilities.
C. All work performed on public or private streets or thorough fares shall be done in such manner
that the operations of other utilities and the convenience of the public will be interfered with as little as
possible and no condition.
D. The construction and maintenance of electronic outdoor plants or systems shall meet applicable
electrical protection and strength requirements in the other section of this Code.
7.1.2.2 I nspection
Plants, in service or out of service, shall be inspected regularly for the purpose of insuring that they
conform with the strength and electrical protection requirement of this Code.
7.1.2.3 Avoidance of Confl ict
A. In the construction of new lines, care shall be taken to avoid unnecessary crossings.
B. Supply and communications lines other than lines on jointly used poles, shall not occupy the
same side of the road (fence, line, construction excluded; where the fence is used as all or part of the
supporting structure) unless the consent of existing party or parties is obtained or where both sides of
the road are already occupied by the same class of line.
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7.1.2.4 Cooperati on to Avoid Conf li ct
Any party contemplating construction or reconstruction which would create a conflict with a line of
another classification or ownership shall notify the party or parties owning or operating the other
installation in advance, of such construction, giving full information as to location and character of the
proposed construction, and the parties concerned shall cooperate with a view of avoiding or, if this is
impractible, of minimizing the hazard to a level considered acceptable in this Code.
7.1.2.5 Abandoned Li nes
Lines or portions of lines no longer required to provide the present or expected service shall be
removed by their owners or operators so that such lines shall not become a public nuisance or hazard.
7.1.2.6 F oreign A ttachments
Nothing in these rules shall be construed as permitting the unauthorized attachment of radio antennas,
ropes, signs and any such equipment foreign to the purpose of the plant.
7.1.2.7 Tr ee Tri mming
A. Where overhead wires passes through trees, safety and reliability of service requires that a
reasonable amount of tree trimming be done.
B. Trees so located that they can fall into a crossing span or into any span that could communicate
the trouble to a crossing span should be removed whenever practicable.
7.1.2.8 Stepping
The lowest step on any stepped pole shall be not less than 2.4 meters from the ground line where
supply conductors are supported on the same pole with communication conductors. On poles supporting
communication conductors only, the lowest metal step may be placed not less than 2.0 meters above the
ground, spacing between steps shall not be less than 1.0 meter, and so placed that runs of risers, etc. do
not interfere with their free use.
7.2 GROUNDING AND BONDING
7.2.1 Earth Ground
The poles or supporting structures of overhead lines shall be provided with an earth ground whose
earth resistance shall be no greater than 25 ohms, measured by the fall of potential methods, and at
intervals not greater than 400 meters.
7.2.2 Bonding
Metallic inner sheath and metallic outer jackets of cables, messengers, guys and all other metallic
hardwares at poles or structure supporting overhead lines shall be bonded together at locations where an
earth ground is present and connected to that earth ground. At locations without an earth ground, metallic
cable outer jackets, messengers, guys and all other metallic hardware shall be bonded together.
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7.2.3 M anholes
All manholes shall be provided with a earth ground whose earth resistance shall be no greater than 25
ohms, measured by the fall of potential method, where metallic inner sheaths and metallic outer jackets of
cables, metallic hardwares, etc. bonded together shall be firmly attached.
7.2.4 Bu r ied Cabl es
Metallic sheaths of buried cables shall be bonded to an earth ground whenever such cable make an
above ground appearance.
7.2.5 Risers
All overhead cables shall have their metallic sheath or jackets grounded whenever such cable changes
from overhead to underground installation with the grounding point as close to group level as practicable.
7.2.6 The earth ground, ground wire run, bonding and attachments shall meet all applicable rules in this
Code.
7.3 JOINT USE OF POLES OR STRUCTURE
7.3.1 Joint use of poles or structures shall be given consideration by all interested parties where
construction or reconstruction is involved and where used, it shall be subject to the applicable strength,
electrical protection and clearance requirements in this Code. Nothing herein shall be construed as
requiring joint use of the same poles or structures without the owner‟s consent.
7.3.2 Each party should designate its space requirements, which space shall not be occupied without
consent, by equipment of any party.
7.3.3 Communication entities owning poles or structures jointly used shall ascertain and be responsible
that strength and electrical protection requirements of this Code are met.
7.3.4 Communication entities contemplating on joint use of poles or structures of other entities shall
ascertain that strength and electrical protection requirements of this Code can be met before jointly using
those poles or structures and further ascertain that such poles or structures are maintained in such manner
that applicable maintenance rules in this Code are met.
7.3.5 Climbing space on jointly used poles or structures shall be provided and correlated between the
entities jointly using the poles or structures that the climbing space position in relation to the pole shall
not change by more than 90 degrees in a vertical distance of less than 2.5 meters.
7.3.6 In case of disagreements between entities jointly using the poles or structures which results in
situation considered hazardous or unacceptable in this Code, the entity covered by this Code shall refer
the matter to the enforcer of this Code for appropriate action or ruling.
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7.4 CLEARANCES
7.4.1 General
A. Where two or more systems are concerned in any clearance, that owner or operator who last in
point of time constructs or erects facilities, shall establish the clearance required in this Code from other
facilities which have been erected previously. Relative to the clearance which it bears to older lines in
the vicinity, each succeeding line erected should be constructed with a view to the requirements of such
older lines when they are reconstructed to the standards which currents rules have specified. Subsequent
entrants into an area shall recognize the rules for future development made by all prior entrants in the
field as indicated by their installed facilities.
B. When supply and communication circuits are involved in crossings, conflicts or joint use, the
higher voltage circuit shall in general be carried at the higher level. The arrangement is not feasible in
all cases, for example where trolley circuits are involved or where poles are jointly occupied and in
such cases applicable clearance requirement in this Code shall be strictly followed.
C. Communication circuits shall not be installed above supply circuits in excess of 7,500 volts.
D. Single conductors paired wire or cable installed above supply circuits of 7,500 volts or lower
shall be adequately supported meeting strength requirements of applicable rules in Section IV and shall
be insulated to continuously withstand the peak voltage that may be present on the supply circuit.
E. Supply circuit of not greater than 300 volts and communication circuits of different or the same
ownership may be supported on the same cross-arm, provided they are installed on opposite ends of the
arm and the nearest conductors of the two circuits are separated a horizontal distance of not less than 1
meter.
F. Clearances specified in succeeding rules in this Section shall be at 60 degrees C. and no wind
loading.
7.4.2Above Groun d
7.4.2.1 Conductors and cables shall have a minimum vertical clearance above ground as follows:
A. Crossing or along public thoroughfares in urban area or crossing public thoroughfares in rural
area, the clearance shall be not less than 5.5 meters.
B. Along public thoroughfares or across other areas capable of being traveled by vehicles or
agricultural equipment in rural areas, the clearance shall be not less than 4.5 meters. The clearance may
be reduced no less than 4.0 meters along the public thoroughfares in rural areas where no part of the
installation overhangs any part of the thoroughfares which is ordinarily traveled and where it is unlike
that vehicles will be required to cross under the installation.
C. In areas accessible to pedestrians only the clearance shall be not less than 3.0 meters for
conductors (open wire) with 160 volts or less transmitting not more than 50 watts and not less than 2.4
meters for cables having grounded metal sheath.
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D. Railway signal cables which are entirely on fenced railway rights-of-way exposed to vehicular
traffic but do not cross public thoroughfares shall have a clearance of not less than 3.0 meters. Such
cables which are entirely on right-of-way and which are in areas accessible to pedestrians only shall
have a clearance of not less than 2.1 meters.
E. Crossings above swimming pools shall be avoided where practicable and when this cannot be
avoided, the clearance above the highest water level of the pool shall not be less than 5.5 meters for
conductors and not less than 4.8 meters for plastic jacketed cable with an inner grounded sheath
together with its grounded messengers or support wires.
F. Vertical runs and risers of conductors and cables do not have clearance requirement to ground.
G. Cables attached to structures and installed in a manner that they do not interfere with the free
flow of vehicular and pedestrian traffic insulated to withstand twice the maximum voltage that may be
present within the cable and fitted with protective covering acceptable to the enforcer of this Code, may
have clearance to ground other than those specified in 7.4.2, provided no hazardous condition results for
such clearance adopted.
H. Temporary installation for temporary service, demonstration, training etc. installed inside private
properties, not exposed to vehicular or pedestrian traffic, may have clearance specified in 7.3.2
provided no hazardous condition results from such clearance adopted.
7.4.2.2 Service drops shall have a minimum, vertical clearance above ground as follows:
A. Crossing or along public thoroughfares in urban area or crossing public thoroughfares in rural
area, the clearance shall be not less than 5.5 meters and may grade from 5.5 meters at a position not
more than 3.6 meters and horizontally from the curb line to a clearance of not less than 4.8 meters at the
curb line, provided the clearance at the center line of any public thoroughfare shall in no case be less
than 5.5 meters. Where there are no curbs the foregoing rules shall apply using the other limits of
possible vehicular movement in lieu of a curb line.
B. Along public thoroughfares or across other areas capable of being traveled by vehicles or
agricultural equipment in rural areas, the clearance shall be not less than 4.5 meters. This clearance
maybe reduce to not less than 4.0 meters along public thoroughfares in rural areas where no part of the
service drop overhangs any part of the thoroughfares which is ordinarily traveled and when it is
unlikely that vehicles will be required to cross under.
C. In industrial and commercial premises accessible to pedestrians only, the clearance shall be not
less than 3.6 meters. In residential premises accessible to pedestrians only, the clearance shall not be
less than 3.0 meters. If the building served does not permit an attachment which will provide this 3.0
meters clearance without the installation of a structure on the building, the clearance shall be as great as
possible but in no case less than 2.6 meters.
D. Over private driveways or lanes, or over private property in industrial and commercial premises
accessible to vehicles, service drop shall have a vertical clearance of not less than 4.9 meters.
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E. Over residential driveways or lanes or over private property in residential premises accessible to
vehicles, service drops shall have a vertical clearance of not less than 3.6 meters. If the building served
does not permit an attachment which will provide this 3.6 meters clearance without the installation of a
structure on the building, the clearance shall be as great as possible but in no case less than 3.0 meters.
F. Service drops on fenced railway right-of-way exposed to vehicle traffic but do not cross public
thoroughfares shall have a clearance not less than 3.0 meters. Service drops entirely of fenced rights-ofway and which are in areas accessible to pedestrians only shall have a clearance of not less than 2.1
meters.
G. Service drop installation above swimming pools shall be avoided where practicable. Where
installed above swimming pool, the clearance from the top edge walls shall be not less than 5.5 meters
and vertical clearance of not less than 5.5 meters above the highest water level pool. Service drops with
coverings of material specially approved by the enforcer of this Code for installation above the
swimming pools may have vertical clearance above the highest water level of the pool and radial
clearance from the top edge of the pool wall of not less than 4.3 meters for public and commercially
operated pools and not less than 3.0 meters for residential pools. No service drop shall be installed less
than 4.3 meters vertically above the horizontal plane through a diving board or platform the area of such
plane being within 2.4 meters radially of the diving board of platform and over the water surface of the
pool.
No service drop may be installed less than 3.0 meters vertically above the horizontal plane through
diving board or platform the area of such plane being the area 1.0 meter radially of the diving board or
platform and not over the water surface of the pool.
7.4.2.3 Guys shall have a minimum vertical clearance above ground as follows:
A. Guys over or across public thoroughfares in urban areas or crossing public thoroughfares in rural
areas shall have a clearance of not less than 5.5 meters above the except that a clearance of not less than
4.9 meters is permitted for the portions of guys over that part of the public thoroughfares which is an
entrance to or exit from industrial or commercial premises; and not less than 4.3 meters in cases where
an entrance to or exit from private residential premises is involved.
B. Overhead guys along public thoroughfares no portion of which overhangs the thoroughfares
ordinarily traveled and there it is unlikely that vehicles will be required to cross under shall have a
clearance of 2.4 meters to ground provided this will not inconvenience adjacent property owners.
C. Portions of guys over private roadways shall have clearance of not less than 4.9 meters in rural
areas and not less than 4.3 meters in urban areas.
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D. Guys shall have a vertical clearance above the highest water level of a swimming pool of not
less than 4.9 meters.
No guy shall be installed less than 4.9 meters above the horizontal plane through a diving board or
platform, the area of such plane being within 2.4 meters radially of the diving board or platform and
over the water surface of the swimming pool. No guy shall be installed less than 2.4 meters vertically
above the horizontal plane through a diving board or platform, the area of such plane being the area
within 1.0 meter radially of the diving board or platform and not over the water surface of the pool.
7.4.3 Above Rail ways and Tr oll ey Li nes
7.4.3.1 The minimum vertical clearance of conductors, open wire, cables and service drops crossing
above railroad tracks not operated by overhead contact wires shall not be less than 7.6 meters which is
based upon the maximum of standard freight cars of 4.7 meters from the top of the rail. This clearance
shall in case be reduced more than 5% because of temperature, wind or mechanical loading.
7.4.3.2 The minimum vertical clearance of conductors, open wire, cables and service drops crossing or
paralleling above tracks of railroads operated by overhead trolley shall be not less than 7.9 meters which
is based upon the maximum height of a free trolley pole throw of 7.9 meters above the rails. Where there
are variances from this assumed value the clearance shall be increased or decreased proportionally except
that in no case shall the clearance be less than 7.6 meters.
7.4.3.3 Service drops may cross above trolley contact conductors, including messenger in catenary
construction, at a vertical distance of not less than 1.2 meters, provided they clear the top of rails a
vertical distance of 7.9 meters where the railway crossed transport standard freight cars or 7.0 meters
where the railway does not transport freight cars.
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Table 7-1 BASIC MINIMUM CLEARANCE IN METERS BETWEEN CONDUCTORS, WIRES,
CABLES AND STRUCTURES.
Item No.
A
B
C
A
Span Wires,
Messengers
and
Guys
Nature of clearance
B
Communications
Condcutors,Open
Wires, Cables,
Service Drops
Between wires, cables and conductors
not supported on the same pole, vertcally at crossings in spans, and radially
where collinear or approaching crossings:
1. Span wires, guys and messengers
0.45
0.6
2. Communication conductors . . . .
0.6
0.6
3. Supply conductor:
a) 0-750 volts . . . . . . . . . . . . . . .
b) 750-7,500 volts . . . . . . . . . . .
c) 7,500-20,000 volts . . . . . . . . .
d) Over 20,000 volts . . . . . . . . . .
0.6
0.9
0.9
1.8
1.2
1.2
1.8
2.4
Vertical separation between conductors
and/or cables on separate cross-arms or
other supports at different levels (except
on related line or buck arm) on the same
pole or structure.
1. Communication conductors and service
and service drops . . . . . . . . . . . . . . . .
0.3
2. Supply conductors:
a) 0-75 volts . . . . . . . . . . . . . . . . . . . .
b) 75-7,500 volts . . . . . . . . . . . . . . . .
c) 7,500-20,000 volts . . . . . . . . . . . . .
d) Over 20,000 volts . . . . . . . . . . . . .
1.2
1.2
1.8
1.8
Vertical separation of conductors on
Related arms and buck arms:
1. Line arms above or below related
buck arms . . . . . . . . . . . . . . . . . .
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Table 7-1 BASIC MINIMUM CLEARANCE IN METERS BETWEEN CONDUCTORS, WIRES,
CABLES AND STRUCTURES.
Item No.
D
A
Span Wires,
Messengers
and
Guy
Nature of clearance
Horizontal separation of conductors
on same cross-arms
1. Pin spacing of longitudinal conductors,
Vertical conductors and service drops. .
E
B
Communications
Condcutors,Open
Wires, Cables,
Service Drops
0.075
Clearance from Structures:
1. Vertical clearance above all signs
Which men can walk. . . . . . . . . . .
2.4
2.4
2. Vertical clearance above all signs
Which men cannot walk . . . . . . . .
0.6
0.6
3. Vertical clearance under signs which
Are illuminated . . . . . . . . . . . . . . . .
0.6
0.6
4. Vertical clearance under signs which
Are non-illuminated . . . . . . . . . . . .
0.15
0.3
5. Horizontal clearance from signs which
Are illuminated . . . . . . . . . . . . . . . . .
0.9
0.9
6. Horizontal clearance from signs which
Are non-illuminated . . . . . . . . . . . . . .
0.15
0.3
7.4.4Between Wires, Conductors, Cables and Messengers
7.4.4.1 Insulated cables are treated as a single conductor and therefore no specified clearance is required
between the individual conductors of the cable.
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7.4.4.2 The basic minimum clearance between wires, conductors, cables and messengers shall be
indicated in Table 7-1 except under the following modifying conditions:
A. I tem A-1 & A-2
1. Not applicable to wires, conductors, cables and messengers of the same entity or system.
B. I tem A-3a
1. Communication service drops crossing below supply conductors of 0-75 volts, or above
supply line cables with metallic sheaths where such metal sheath is adequately grounded, may have
a vertical clearance less than 1.2 meters as listed in Table 7-1 item A-3a but shall not less than 0.6
meters, provided the crossing is 1.8 meters or more from any pole which supports any conductors
involved in the crossing but which does not support both conductors involved in the crossing.
2. Radial clearance between communication service drops and supply service drops may less be
less than 1.2 meters as listed in Table 7-1 item A-3a but not less than 0.6 meters. Where within 4.5
meters of the point of attachment of either service drop on a building or structure, this clearance
may be further reduced but shall not be less than 0.3 meters.
C. I tem A-3b
1. Where communication conductors cross under or in conflict or collinear with supply
conductors of 750-7500 volts within 1.8 meters radially of a pole or structure which supports the
communication conductors, the vertical clearance listed in Table 7-1 A-3b of 1.2 meters shall be
increased to not less than 1.5 meters.
D. I tem A-3d
1. For supply voltages over 200,000 volts, the clearance in Table 7-1 A-3d of 1.8 meters and 2.4
meters shall be both be increased to not less than 3.9 meters.
E. I tem B-1a
1. On poles which carry on cross-arms, open wire conductors attached to the sides of poles by
means of hooks, knobs or brackets may be placed in any position within the 1.0 meter next below
the topmost conductor on the pole. The vertical separation between conductor supports on the same
side of the pole in this space 1.0 meter shall not be less than 0.15 meters. Below this point (1.0
meter below the topmost conductor) conductors shall be attached to one side of the pole only, not
more than 6 conductors shall be so attached, and the vertical separation between there conductors
shall not be less than 0.3 meters.
2. On poles which carry communication cross-arms only, one pair of open wire conductors may
be attached to opposite sides of the pole be means of hook, knobs or brackets, at a point not less
than 0.6 meters below the lowest level of conductors supported on cross-arms. Below this point (0.6
meter below conductors on cross-arm) other conductors which are attached to the surface of pole
shall be attached to one side of the pole only, not more than 6 conductors shall be so attached, and
their vertical separations shall be not less than 0.3 meters.
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3. Branch or top lines and service drops from conductors attached to poles may be similarly
attached to the face or back of a pole but not on both.
4. On poles which carry no supply conductors and no cross-arms, communications cables or
messengers attached to the sides of poles may be placed in any position the 1 meter of the top of the
pole provided metal-sheathed cables or messengers are separated from open wires conductors in
this section of the pole by a vertical distance of not less than 0.3 meters.
5. The clearance listed in Table 7-1 item B-1a does not apply to insulated conductors and cables
of the same entity or system.
F. I tem B-2a
1. Cables or messengers were attached to the surface of poles which support supply conductors,
shall not be less than 1.8 meters vertically below the level of supply conductors, except that this
minimum clearance of 1.2 meters may be reduced to not less than 0.9 meters below supply
conductors of 0-750 volts provided a guard arm is placed above the messenger and cable or selfsupporting cable. The guard arm at least 1.2 meters in length, shall be placed directly above and as
nearly parallel as practicable to longitudinal aerial cables or messengers over which a guard arm is
required. In lieu of the guard arm a suitable wood covering of the length specified for guard arms
may be placed around the cable and messenger.
G. I tem B-2d
1. For supply voltages over 200,000 volts, the clearance in Table 7-1 B2d of 1.8 meters shall be
increased to not less than 3.9 meters.
H. I tem C-1
1. The clearance of 0.15 meter specified in Table 7-1 item C-1 is not required between
conductors on line arm and related buck arm where the conductors supported by such arms do not
cross.
I. I tem D-1
1. Not applicable to insulated conductor/s or cables whether single or grouped and whether with
or without supporting messengers.
7.4.5 F r om Str uctur es
7.4.5.1 The basic minimum clearance of wires, conductors, cables, and messengers from signs
mounted on buildings and isolated structures shall be as indicated as Table 7-1 except under the following
modifying conditions:
A. I tem E-3 and E-5
1. The clearance specified in Table 7-1 item E-3 and E-5 may be reduced when the sign is
grounded but shall not less than 0.15 meters for span wires, guys and messengers, communication
cables and services drops and not less than 0.3 for open wire conductors.
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B. I tem E-4 and E-6
1. The clearance specified in Table 7-1 item E-4 and E-6 may be reduced if adequate separation
is provided by means of a suitable non-conducting separator but shall be not less than 7.5 cm. for
span wires, guys and messengers, communication cables and shall service drops.
7.5 CLIMBING SPACE
7.5.1 The climbing space shall be provided on one side or quadrant of all poles or structures
supporting communications conductors excepting at the level of one pair of conductors attached to the
pole below the lowest cross-arm and the top 0.9 meter of poles carrying communication conductors only
which are attached directly to the pole.
7.5.2 The climbing space shall be maintained in the same position on the pole for minimum vertical
distance of 1.2 meters above and below each conductor level through which it passes, excepting that
where a cable is attached to a cross-arm or a pole with the cable less than 0.2 and 0.4 meters from the
center line of the pole supporting conductors on line arms.
7.5.3 The position of the climbing space shall not be shifted more than 90 degrees around the pole
within a vertical distance less than of less than 2.4 meters.
7.5.4 Vertical conductors, when in a suitable protective covering attached directly to the surface of
the pole, terminal boxes or similar devices which do not extend more than 14 cm. from the surface of the
pole, and guys, will not be held to obstruct the climbing space provided not more than one guy and one
other of the above named obstruction are installed in any 1.2 meter vertical section of the climbing space.
7.5.5 Cross-arms and their supporting members are allowed in climbing spaces provided that, where
buck arms are involved, any arms within in climbing spaces are treated as double arms.
7.5.6A guard arm, a longitudinal run of messenger, cable or insulated wire will not be held to obstruct
the climbing space where because the presence of a building wall or similar obstacle will not permit the
cable to be placed on the side of the pole opposite the climbing space.
7.5.7 Pole steps shall be suitably placed for the purpose of facilitating climbing past the level of
terminal boxes, cable, drop wires, and guard arm.
7.6 VERTICAL RUNS, RISERS, GROUND WIRES
7.6.1 Vertical runs of communication wires or cables supported on the surface of wood poles or
structure shall be covered by a suitable protective covering within a vertical distance of 0.9 meters above
1.8 meters below unprotected supply conductors supported on the same pole or structure. Vertical runs of
communication wires or cables on surface of a wood pole shall be covered by a suitable protective
covering within 1.8 meters radius of any other pole supporting supply conductors except that those
portion of such runs which are more than 0.9 meters above or 1.8 meters below the level of unprotected
supply and conductors need not be covered. The protective covering shall be rigid polyvinyl chloride
plastic pipe with a minimum wall thickness of 6 mm. or equivalent. Cables and drop wire runs to or from
terminal boxes are exempted from these requirements for covering under the following conditions.
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a) Where guard arms are installed above messengers or longitudinal cables which are less than 1.8
meters below but not less than 1.2 meters below unprotected supply conductors of 750 volts, or where
cables are supported on cross-arms at not less than 35 cm. from center line of pole, in which case any
portion of metal sheathed cable runs on the surface of the pole below the guard and in the same
quadrant as the longitudinal cable, or below and on the same side of the poles with a cross-arm which
supports a longitudinal cable.
b) Runs of briddled conductors attached to the surface of the pole, need not to be covered provided
such runs are below the guard arm and in the same quadrant as the longitudinal cable, or where such
runs are below on the same side of the pole with a cable arm and are not in the climbing space. When
briddled runs are not required to be covered, they shall be supported by briddle hooks or rings spaced at
intervals of not more than 0.6 meters.
Runs which terminate in the top enclosure which afford ample mechanical protection the runs, may
extend within 2.4 meters of the ground without being treated as risers.
Vertical runs shall be treated as risers where within a distance of 2.4 meters from the ground.
7.6.2 Risers
Risers of wires or underground cables shall be encased in securely grounded metal or plastic pipe
from the ground line to a level not less than 8 feet above the ground line.
Risers shall be covered by a suitable protective covering as defined in Rule 7.6.1 where within a
vertical distance of 0.9 meters above or 1.8 meters below the level of unprotected supply conductors
supported on the same pole or structure.
Vertical risers where within both a 6-foot radius of another pole supporting supply conductors and
within vertical distance of 0.9 meters above or 1.8 meters below the level of any unprotected supply
conductor shall be covered.
7.7 GUYS AND ANCHORS
7.7.1Where the mechanical loads imposed on poles, towers, or structure are greater than can be
supported with the safety factors as specified in Rule 4.3.2 under the loading condition of Rule 4.2.,
additional strength shall be provided by the use of guys or other suitable construction.
7.7.2 Where guys are used with poles or similar structures capable of considerable deflection before
failure, the guys shall be able to support the entire stress, the pole below the point of guy attachment
acting merely as a strut.
7.7.3 Guys shall be attached to structures as nearly as practicable at the center of load. They shall be
maintained taut and such strength as to meet the safety factors of Rule 4.3.2 under the loading condition
of Rule 4.2.
7.7.4 Guy wires shall be protected by the use of guy thimbles or their equivalent when attached to
anchor rods or though bolts.
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7.7.5 Soft wood poles, around which any guy having an ultimate strength of 2,300 kg. or more is
wrapped, shall be protected by suitable guy shims. Hooks, lag screws or other equivalent means shall be
used where necessary to prevent the guy from slipping along the pole.
7.7.6 The general requirements governing the sectionalizing of guys by means of insulators are based
upon the exposure or proximity of the group to supply conductors. The following requirements shall
apply to the treatment and sectionalizing of guys.
A. Guys attached to or passing poles or structures supporting only communication conductors need
not to be sectionalized provided such guys are not exposed or not in proximity to supply conductors.
B. Overhead or anchor guy any portion of which is exposed or in proximity to supply conductors
shall be sectionalized by means of insulators and no portion in proximity to such supply conductors
shall be grounded. Exempted from this requirement are anchor guys and grounded overhead guys,
which are attached to poles at a level less than 2.4 meters but not less than 1.8 meters below the level of
supply conductors, provided the level of the guy attachment is at or below the level of communication
cable messenger attached to the same pole. Also exempted from this requirement are anchor guys, and
grounded overhead guys, which are attached to poles at a level less than 1.8 meters but not less than 1.2
meters below the level of supply conductors of 750 volts provided such guys are extension of or
attached to a cable messenger, are in the same vertical plane (or extension thereof) as the messenger,
and are below the guard arms required for such a messenger.
C. Guys attached to securely grounded metal poles or structure are not required to be sectionalized
except when in proximity to supply conductors of less than 20,000 volts.
D. All insulators in overhead guys shall not be less than 2.5 meters above the ground.
E. Overhead guys to be sectionalized shall have an insulator not less than 1.8 meters and not more
than 2.8 meters (measured along the guy) from each point of attachment to wood poles or structure
which support conductors. One insulator will suffice where such an overhead guy is less than 5.2 meters
in length between wood poles or structure.
F. An insulator shall be installed to each anchor guy which is required to be sectionalized so that
such insulator is located not less than 2.5 meters above the ground and either 2.5 meters below the level
of the lowest supply conductor or not less than 1.8 meters from the surface of the pole and not less 0.3
meters below the level of the supply conductor. These sectionalizing requirement for anchor guys can
normally be met by insulation at one location, however, long guys or other conditions may require
insulation at two locations; one location being not less than 2.5 meters above the ground and the other
location either not less than 2.5 meters below the lowest supply conductors, or not less than 1.8 meters
horizontally from the pole and not less than 0.3 meters below the level of the lowest supply conductor.
G. Trees, buildings, messenger and other objects shall be prevented from grounding portions of
guys sectionalized and not supposed to be grounded.
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7.7.7 Insulators with sectionalized guys shall conform to the following specifications based on the
highest voltage of supply conductors such guys is exposed or in proximity.
A. Insulators shall be porcelain, glass or other equally suitable material.
B. Insulators used in guys on communication lines shall be so designed that their dry flashover
voltage is not more than 75% if their puncture voltage at the operating frequencies of supply lines to
which the guys are exposed.
C. Insulators shall have a dry flashover voltage not less than as specified in Table 7-2 under the
mechanical loadings specified in this Code for the guy construction involved.
Table 7-2
GUY INSULATOR FLASHOVER VOLTAGE
Nominal Voltage of Circuits
Nearest Point of Attachment
Dry Flashover
Voltage of Insulation
0-7,500 volts
7,500-17,500 volts
Over 17,500 volts
15,000 volts
Double the circuit voltage
35,000 volts
7.8.8 A substantial guard of wood, metal, plastic or suitable material, not less than 2.5 meters in
length, shall be securely attached to each anchor guy which exposed to traffic.
7.8 MISCELLANEOUS EQUIPMENT
7.8.1 On jointly used poles, metal communication cable terminals, metal boxes or similar equipment
which are less than 0.2 meters from center line of the pole or are attached to the surface of the pole shall
be placed not less than 1.8 meters below or 0.9 meters above the level of the nearest unprotected supply
conductor.
7.8.2 All parts of metal communication cable terminals, metal boxes or similar equipment which are
0.2 meters or more from the center line of the pole shall have vertical clearances from supply conductors
not less than specified in Table 7-1 item B-2a to d.
7.8.3 Where a telephone instrument is attached to the surface of a pole or structure at less than 2.4
meters vertically above the ground (or at any elevation on a grounded metal pole or structure) and is
connected to a communication circuit, such instrument shall be enclosed in a suitable box of insulating
material, which may be locked to prevent access by unauthorized persons. Where such a telephone
instrument is so attached, connected and enclosed, unless isolated from the communication circuit by an
adequate insulating/protecting device, a suitable insulated mat or platform, on which a person can stand
while using the instrument, shall be provided.
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VIII. TOWERS AND SUPPORT STRUCTURES
8.1 APPLICABILITY
8.2 GENERAL REQUIREMENTS
8.3 STRENGTH REQUIREMENTS
8.3.1 Loading
8.3.2 Foundations and Anchors
8.3.3 Guys
8.3.4 Fabrication and Erection
8.3.5 Inspection and Maintenance
A. Wood Poles
B. Metal Poles
C. Inspection Intervals
D. Markings
8.4 ELECTRICAL PROTECTION REQUIREMENTS
8.4.1 Grounding
8.4.2 Bonding
8.4.3 Markings
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SECTION VIII
TOWERS AND SUPPORT STRUCTURES
8.1 APPLICABILITY
Tower poles and other support structures although within the purview of other engineering
disciplines, particularly strength considerations, have become integral and inseparable components of
electronic and communication systems in such a way that electronic and communication system
specifications cover towers, poles and other support structures when such are needed in the system to
provide the service desired.
8.2 GENERAL REQUIREMENTS
8.2.1 All towers, poles, and other support structures, their components and allied structures used in
electronic or communication plants supporting radio antennas, communication wires and cables, radio
transmission lines and waveguides, and all like shall be able to withstand, with safety factors not less than
those specified in Rule 4.3.2, the maximum stresses to which they are subjected under the loading
conditions specified in Rule 4.2, without structural damage.
8.2.2 All towers, poles, other support structures, their components and allied structures used in electronic
and communication plants supporting radio antennas, communication wires and cables, radio
transmission lines and waveguides and the like shall be constructed and maintained to assure that shock,
casualty or fire hazard shall not result from its use and during conditions resulting in the presence of
foreign potential due to lightning and/or power contact.
8.3 STRENGTH REQUIREMENTS
Antenna towers, poles and related structures shall be designed to withstand with safety factors not
less than those specified in Rule 4.3.2, the maximum stress to which they are subjected under the loading
conditions specified in Rule 4.2 without structural damage.
8.3.1 Loading
A. Wind loading shall be considered as basic loads with no increase in the basic allowable unit
stresses.
B. Wind pressure on the projected area of a structure shall be calculated in accordance with
accordance with methods acceptable and in use by the appropriate engineering discipline and/or
specified in the appropriate Code of Practice enforced by the government.
C. Wind pressure of projected area on cylindrical surfaces shall be computed as being 60% of that
for flat surfaces.
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D. For open face latticed structures of square cross section the wind pressure shall be applied to
1.75 times the normal projected area of all members in one face and for open face latticed structures of
triangular cross section the wind pressure shall be 1.5 times the normal projected area of all members in
one face; provided this computation does not indicate a greater pressure than would occur on a solid
condition, in which case the latter shall be taken. For closed faced, solid structures, the wind pressure
shall be applied to 1.0 times the normal projected area.
E. For solid microwave parabolic antennas/reflectors the maximum axial or thrust force occurs at a
wind angle of 56° from normal and shall be computed in accordance with the formula.
F = CAV2
Where: F = Axial thrust force in kg.
C = coefficient
A = frontal area in square meter
V = wind velocity
The load coefficient C, in relation to the wind angle shall be:
Wind Angle in degrees
Load Coefficient (C)
0
45
56
90
125
180
+0.00754
+0.00801
+0.00829
+0.00047
+0.00235
+0.00508
F. Dead Loads  Provisions shall be made of all supplementary loading caused by the attachments
of guys, antennas, transmission and power lines, ladders, rest platforms, etc. Ladders and rest platforms
and all allied climbing attachments to the tower shall be capable of supporting a live load of 120 KG
with a design safety factor of not less than 2 under the loading conditions specified in Rule 4.2.
G. Seismic Loads

The total lateral seismic force on any structure shall be calculated in
accordance with the following formula or other methods acceptable and in use by the appropriate
engineering discipline and/or specified in the appropriate Code of Practice enforced by the government.
F = ZCW
Where: F = lateral force
C = shear coefficient (typical 0.10)
W = total dead end
Z = zone coefficient
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H. The total load specified in Rules 8.3.1.A, 8.3.1.F and 8.3.1.G shall be applied to the structure in
the directions which will cause the maximum stress in the various members.
I. The allowable unit stresses and combined stresses resulting from the specified design loads for all
structural members, bolts, threaded parts and their associated joint configuration, anchors, and
foundations, shall not exceed those specified in the appropriate Code of Practice enforced by the
government.
8.3.2 Foundations and Anchors
A. The individual footing under each leg of self-supporting towers shall be designed to resist not
only downward force but also an upward pull from the overturning moment caused by wind load.
B. The footing of guyed towers shall be designed to resist downward force only (due to the weight
of the structure; antennas and transmission lines together with their support structures; and the vertical
components of guy pulls) and a generally moderate horizontal wind reaction.
C. Reduction in weight of material due to buoyancy (hydrostatic uplift) caused by high water tables
shall be considered. The soil properties as affected by submerged conditions saturated soil, etc. shall be
considered in the foundation and anchor design utilizing recognized engineering methods with safety
factor of 2 for uplift.
D. All foundations and anchors shall be designed for the maximum combined dead and live loading
expected with a safety factor of not less than 2.
8.3.3 GUYS
A. The factors of safety of guys and their connections shall be not less than 2. The factor of safety
of guys shall be calculated by dividing the ultimate strength of the guys (modified by a factor as
required by the type of connections and/or insulators used) by the maximum calculated working stress
at the design load.
B. Guys should be installed with an initial tension of one-sight of its breaking strength. On cases
where guy vibrations are noticeably large, mechanical damper should be installed near the bottom of
each guy to reduce vibration to an acceptable amount.
8.3.4 Fabrication and Erection
A. All tower fabrication and erection shall be undertaken with the end in view of producing a
structure and parts thereof that will not fail or be seriously distorted at any load less than the maximum
working loads developed under the construction arrangement with loadings as specified in Rule 4.2
multiplied by the safety factors specified in Rule 4.3.2.
B. For guyed towers the maximum deviation from true vertical shall be one part of 400. For selfsupporting towers the maximum deviation from true vertical shall be one part in250.
C. Roof mounted towers are sometimes required and this will require careful evaluation of the
structural adequacy of the building to support the proposed tower.
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8.3.5 Inspection and Maintenance
This section covers inspection information relative to both wood and metal poles and towers. The
purpose of pole/tower inspection is to assure proper maintenance of poles and towers and reinforcement
or replacement of poles and towers in advance of their reaching that stage when the safety factor have
been reduce to less than 2/3 of the safety factors specified in Rule 4.3.2
A. Wood Poles
a) Inspection consists primarily of determining the amount of sound wood at the section where
the pole is likely to fail, comparing this sound wood with the minimum amount required at that
section for the pole being inspected.
b) Fiber strength, used in obtaining the minimum allowable dimension, is determined by the
species of pole timber under inspection and is shown in Table 4-2.
c) Where it is necessary to examine the condition of poles below ground level, dig out from
around the pole sufficiently to permit the inspection of the butt at the section of maximum decay.
The exact location and extent of such decay must be determined by prodding or by a boring test.
d) If a pole is entirely surrounded by concrete or pavement and if sounding indicates a doubtful
condition, make a boring test. Bore at 9.5 mm hole near the ground line and at an angle that
intersects the probable decay at the lowest possible point. The extent of decay close to the ground
line can be approximated by exploring the section with a prod.
e) Whenever a hole is bored in a pole and replacement of the pole is not required, plug the hole
using a wooden plug.
f) All excavations shall be lack filled and thoroughly tamped to the original ground level.
g) Visually inspect all pole surfaces, paying particular attention to such details as insect
infestation lightning damage, etc. Any damage area shall be examined internally and externally to
determine the extent of damage and probable effect on pole life.
h) Test each pole from the ground line to the maximum convenient height within arm‟s length.
Strike the pole sharply with a hammer at closely spaced intervals. A decaying pole sounds dull or
hollow and in some cases, the wood gives under the impact of the blow. A pole free of decay
produces a solid sound, and the hammer rebounds noticeably when the pole is struck sharply. An
increment borer shall be used in all cases where testing indicates a hollow pole. Borings provide
information regarding the extent of decay and shell thickness.
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B. Metal Poles
a) Inspection consists primarily in locating corroded metal tower sections and all parts
thereof and determining its effect on tower life.
b) Loose bolts, braces, etc. shall be tightened and corrosion shall be arrested and
preventive measures taken.
C. Inspection Intervals
All poles and towers shall be inspected at least once every two years.
D. Marking
All poles and towers that are found to have two years or less anticipated life are
condemned for other reasons shall be marked immediately with a danger sign as shown in
Figure 8-1. The danger sign shall be placed below the pole or tower number if any or
approximately 2 meters above ground line facing on-coming traffic.
8.4 ELECTRICAL PROTECTION REQUIREMENTS
Depending upon the surroundings, the presence of antenna and its supporting structure may
not increase the probability of lightning striking a particular location, however, should lightning
strike the site, the antenna and its supporting structure may become the focal point of the strike.
Consequently, the protection grounding considerations for the antennas and support structure
becomes of prime importance.
8.4.1 Grounding
A. Poles, towers and other structures supporting antennas shall be fitted with a grounding
conductor, from the top of the structure running the full length down to the bottom of the
structure, connected to the main ground.
B. The ground resistance measured at any point in the grounding system shall be not greater
than two 5.0 ohms as measured by the fall of potential method.
C. The ground wire around a self-supporting tower shall be placed not less than 30 cm. below
grade level and no less than 30 cm. from outside face of the concrete piers.
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Fig. 8-1
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D. The ground ring shall be cad welded (or other similar method) to the grounding plate twice at
each tower leg, to ground rods, and to the station main ground.
E. Ground rods shall be of galvanized steel or other corrosion-resisting material treated material not
less than 15 mm. in diameter and not less than 2.0 meters long unless their length is otherwise indicated
by calculation from the earth resistance measurements. These ground rods shall be spaced around the
tower at locations from 1.8 to 3.0 meters apart. If these ground rods cannot be placed, the ground wire
shall be connected to radial buried wires specified in Rule 8.4.1.F.
F. When bedrock prevents placement of a ground rod, a network of buried grounding conductors
radiating from each base of the antenna structure and connected to the ground rings shall be provided.
The radiating ground conductors shall be no less than No. 10 AWG solid bare copper or its equivalent
and buried at a depth of between 30 to 45 cm. below grade level. The radiating ground conductors shall
have adequate contact with the soil and shall each be no less than 8 meters in length.
G. Antenna supporting structures poles and towers shall be fitted with lightning rod mounted at the
topmost portion of the structure and at least 30 cm above the highest element of the structure and
connected to the grounding conductor running the full length of the pole, tower or structure.
H. Lightning rods shall be 16 mm. in diameter, of corrosion resisting material such as coppercovered steel or galvanized iron.
I. For guy wires anchored in concrete, three 15 mm. galvanized, copper-covered or other similar
material ground rods shall be driven in a triangular pattern around each anchor and connected to each
other and to the guy wire at least with No. 2 AWG copper wire or its equivalent.
J. All bonds to the steel (except those under tension) and all buried connections shall be brazed (or
other similar process). Pressure clamps shall be used for bonds under construction.
K. Grounding conductors must not be welded to structural members of the towers, including guys
and anchor rods. At the base of the tower, the grounding conductor may be brazed to the heavy
horizontal plate, or clamped to a structural member using a clamp that does not require drilling a hold in
the structural member. The grounding conductor guys shall be clamped above ground to the anchor rod,
clamped to all tensioned guy wires then brazed to the ground rod.
L. Grounding conductors shall be run in as straight a line as practicable to the ground electrode
devoid of sharp bends, kinks, etc.
M. When more than 7.5 meters separation exists between the tower and building, the waveguide
used shall be grounded at both places.
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8.4.2 Bonding
The principles of common grounding and bonding of all metal parts provide the best protection for
personnel, equipment and structures by reducing the possibility of potential differences with its attendant
shock hazard to personnel and arcing resulting in damage to structures.
A. Antenna elements at ground potential, its structure, supports, etc. shall be permanently and
effectively grounded without intervening splice.
B. All bonds in the grounding system shall be in accordance with Rule 8.4.1.J and 8.4.1.K.
C. For metal antenna supports mounted on buildings with metal frame, the antenna support and
waveguide or outer conductor of coaxial cable shall be bonded to the metal frame of the building with
No. 2 copper wire or equivalent.
D. For antenna supports mounted on buildings without a metal frame and where there is less than
1.6 meters separation between them a grounded antenna support or grounding conductor and lightning
protection wires or other grounded building parts such as metal pipes, conduits, smoke pipes, etc., a No.
2 AWG copper wire bond shall be installed. Less massive metal objects, such as gutters, downspouts,
etc. shall be bonded at their upper end to the grounding conductor and if the metal object is of
considerable length, it shall also be bonded at the lower end.
E. The metal framework supporting waveguides, coaxial cables, etc. shall be bonded to the metal
plate at the entrance of the building and at a point of attachment to the lower.
F. Waveguide and coaxial cables shall be bonded to the metal plate at the entrance to the building
and the metal plate bonded to the grounding conductor using No. 2 AWG copper wire or its equivalent.
8.4.3 Markings
Obstruction lightning and painting shall be in accordance with the latest requirement of the
appropriate government agency.
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IX. CONSUMER PRODUCTS
9.1 APPLICABILITY
9.2 GENERAL REQUIREMENTS
9.2.1 Construction
9.2.2 User Servicing
9.2.3 Power Supply Connection
9.2.4 Wiring Devices
9.2.5 Fuses
9.2.6 Transformer
9.2.7 Capacitors
9.2.8 Batteries
9.2.9 Wiring
9.2.10 Insulating Materials
9.2.11 Conductive Coatings and Shields
9.2.12 Connectors, Components and Leads
9.2.13 Voltage Limiting Means
9.2.14 Current Carrying and Live Parts
9.2.15 Enclosures
9.2.16 Accessories
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SECTION IX
CONSUMER PRODUCTS
9.1 APPLICABILITY
This Section establishes safety provisions for the construction, use and maintenance of noncommercial electronic devices such as radio and television receivers, transceivers, amplifiers, tape/disc
players/recorders, intercommunication devices, photographic and similar electronic equipment and their
accessories for household use.
9.2 GENERAL REQUIREMENT
9.2.1 Construction
A. The construction of the appliance shall assure that normal use and user servicing does not result
in a shock, casualty of fire hazard; that the materials and components are used within their electrical,
mechanical and temperature limits, and that the assembly will protect the components and wirings from
being displaced or damaged.
B. Cellulose nitrate or any comparably flammable material shall not be used for a cabinet, cabinetcovering material, dial, window or similar part.
C. Material for the mounting of uninsulated line parts that involved a power of 50 watts or more
shall be flame-retardant or self-extinguishing. Components involved are connectors, printed wiring,
boards, terminal strips, tube and transistor sockets, deflection yoke, coil forms etc.
D. Recording disc or tape shall not be formed or coated with cellulose nitrate or comparable
flammable material and the hazards of storing the disc, tapes, etc. shall not be greater than those
presented by common newsprint in the same general form and quality.
E. A spacing of 13 mm. minimum over surfaces or through air shall be maintained between
uninsulated live parts of the supply circuit and (1) line parts of opposite polarity and (2) accessible
metal parts; except when the location and relative arrangement of the parts are such that adequate is
assured.
F. Except for insulation built into a component, a barrier or liner of fiber or similar material
employed where spacing would otherwise be insufficient between uninsulated line parts of opposite
polarity or between such parts and exposed or partially protected metal parts, shall be 1 mm. thick
minimum. A barrier or liner used in conjunction with an air spacing may be 0.5 mm. thick minimum
provided it is (1) a suitable insulating material, (2) resistant to moisture, (3) of adequate mechanical
strength if liable to mechanical injury, (4) reliably held in place and (5) located so that it will not be
affected adversely by operating the appliance.
G. Unless an acceptable barrier is provided, there shall be a spacing through air of 3 mm. minimum
between the uninsulated live parts of a fuse and fuse clip and (1) uninsulated live parts of opposite
polarity, and (2) the chassis or metal in electrical connection with the chassis. The spacing shall be
determined with the fuse in place.
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H. If shock hazard results from an electrical connection between the external conductive coating of
the picture tube, and the picture tube mounting means (straps, brackets, etc.) that contact the tube, there
shall be a spacing of 13 mm. minimum between the conductive coating and the mounting means. The
spacing shall be measured over the surface of the tube.
I. Casualty hazard is considered to exist if moving parts such as gears and linkages are accessible
during normal operation. Exceptions are moving parts that are accessible only through the bottom or
underside of console/chair type enclosure or drawer is located not more than 15 cm. above the floor and
the moving parts are excessed at least 7.5 cm. from the front edge and side of the enclosure or drawer.
J. Fire hazard is considered to exist at any component connected across a supply circuit, either
under normal conditions or when the chassis and all user connections are grounded while the power
supply rectifier and any two elements of one other vacuum tube, transistor or similar solid state device
are short-circuited, unless one or more of the following condition exist;
a) there is additional series impedance of not less than 10,000 ohms, exclusive of any adjustable
or variable air dielectric capacitor in a circuit when the voltage is 125 volts or less.
b) there is additional series impedance of not less than 20,000 ohms, exclusive of any adjustable
or variable air-dielectric capacitor in a circuit where the voltage is more than 125 volts but not more
than 250 volts.
c) combustible material such as surgical cotton shall not be ignited under any service conditions
of breakdown or failure of the part itself.
K. To be free from fire hazard, the source of power for a component part or assembly shall not be
capable of delivering a power of more than 15 watts into an external resistor connected between any
two points on the assembly with all components in place and:
a) if the source of power is directly from the secondary winding of an isolating type transformer
the conditions of loading to maximum power and of short circuiting the secondary winding shall not
produce a fire or shock hazard.
b) if the source of power employs a resistor to limit the power to 15 watts or less, any conditions
of loading to maximum power or short circuiting the points in question shall not cause the resistor to
change value to the extent that the 15-watt limit will be exceeded.
c) the short or open circuiting (singly) of any rectifier, vacuum tube, transistor, or electrolytic
capacitor between the 15-watt point and the power supply circuit shall not cause the 15-watt limit be
exceeded.
d) an isolating type of transformer shall be capable of withstanding without breakdown for a
period of 1 minute, a 900 volts AC at 60 Hertz between (1) any live-metal part conductively
connected to the supply circuit and any dead metal parts and (2) any live or current carrying part of
the primary power supply circuit and only live or current-carrying part of the secondary circuit.
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L. Shock hazard shall be considered to exist at an accessible part in a circuit when one or more of
the following conditions exist:
a) If the current through a load of not less than 500 ohms exceeds 300 milliamperes after 0.0003
second;
b) If the current through a load of not less than 500 ohms exceeds 5 milliamperes after 0.2
seconds;
c) If the time required for the current through a load of not less than 500 ohms to decrease to 5
milliamperes is between 0.1 and 0.2 second, and the total quantity of electricity passed through the
load up to that time exceeds 4 millicoulombs.
d) If the time required for the current through a load of not less than 500 ohms to decrease to 5
milliamperes is between 0.03 and 0.1 second and the total quantity of electricity passed through the
load up to that time exceeds 75T – 350T2 millicoulombs where T is the time in seconds.
e) If more than 30 milliamperes can be drawn through a load of 1500 ohms.
The current referred to above refers to the current that can be drawn through a load connected to the
accessible part and floor, ground or any other exposed metal part within reach by an adult person (1.5
meters).
M. Any adjustable or variable air-dielectric capacitor and the heater-to-cathode insulation of
vacuum tubes shall not be relied upon to eliminate shock hazard.
9.2.2 User-Servicing
User-Servicing includes the following:
A. Battery  Replacement of a battery except one designed to be soldered in place.
B. Fuse  Replacement of a fuse except:
1) one designed to be soldered in place.
2) one not readily perceptible by the user. A fuse is not readily perceptible if located within a
chassis, compartment, or enclosure within the overall appliance that makes the fuse invisible to the
user. If the enclosure has a cover, it is to be one that (a) does not need to be opened or removed in
normal operation or user-servicing, (b) can be opened or removed only with a tool, (c) is prevented
from being discarded. A fuse is readily perceptible if recognizable during normal operation or userservicing either visually or by touch; or if the fuse is indicated either on the appliance or on literature
packed with it.
3) a clipped-in type that is within a compartment provided with the marking described in Rule
10.7.10. (No User-Serviceable Parts Compartment Warning).
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C. Pilot Lamp  Replacement of a pilot lamp except:
1) One designed to be soldered in place.
2) a filament type lamp which (a) is rated at 28 volts or less,
(b) has an estimated life at the operating voltage or at the voltage resulting from failure of any one
user serviceable component of not less than 20,000 hours for a lamp energized only while the appliance
is “on”, and (c) is connected in a circuit in which the increased voltage incident to switching, user servicing, or any operational characteristic of the appliance does not exceed 120 percent of the voltage
recommended to provide the anticipated life required. Except for item (a), the serviceability of a
gaseous-discharge-type lamp is determined in the same manner as for a filament-type lamp. Other types
of lamps will be given special consideration with respect to the intent of the requirements.
3) A gaseous-discharge-type lamp under the conditions described for a filament-type lamp
without limitation on voltage rating.
4) Any other type of lamp considered with respect to the intent of the requirements.
D. Picture Tube  Replacement of a picture tube except:
1) A directly-viewed typed less than 15 cm. diameter maximum which obviously is not intended
for replacement because it requires removal of rearrangement of major components such as chassis,
printed wiring assembly, deflection yoke, etc.
2) Directly-viewed types having a maximum diameter of 15 cm. or more.
3) Projection type if house in separate enclosure making the tube inaccessible except by the use of
a tool, and if the enclosure is marked in accordance with rule 10.1.14. (Projection-type Picture Tube
Warning).
E. Vacuum Tube and Vibrator  Replacement of a vacuum tube and vibrator except:
1) Tubes design to be soldered in place.
2) For an appliance employing vacuum tubes of the plug-in type, one tube and/or vibrator are not
subject to user-servicing of the tube and/or vibrator are (a) located within the chassis, (b) not visible,
(c) accessible only by use of a tool and (d) not marked on the appliance or on literature packed with it.
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F. Picture Tube and Window Cleaning  The cleaning of a pict ure tube or windows, if access to
the parts to be cleaned can be gained using ordinary tools and without removing the chassis or the
picture tube from the cabinet. During the cleaning operation live parts are considered adequately
protected if:
a) The front cover of a picture tube enclosure can be opened for cleaning or other user-servicing
only after first opening an in interlock cover and if the warning described in Rule 10.7.12.
(Removable Front Cover Warning), is located on the cabinet where readily visible when the front
cover is opened.
b) A barrier, such as a mask, that renders live parts inaccessible during removal or opening of a
picture tube window, is (1) secured in a permanent manner, such as by nails, or (2) is secured
independently of the window mounting, requires a tool for removal and is marked as required in Rule
10.7.1.3 (Picture Tube Window Barrier Warning).
9.2.3 Power Supply Connections
A. Power Supply Cord  the power supply cord shall be in accordance with Table I. An equivalent
or heavier type of cord may be used.
Table I
SUPPLY CORDS
Appearance
Radio and Television
Receiving Appliance
Coffee-Table appliance
Finished on all four sides
And intended for use in
The center of the room
Television Camera
Portable, combination
Supply circuit and batteryOperated radio receiver,
Recorders, etc. rate 60 watts
Or less, with integral cordStorage compartment
Cord Type or
Equivalent
Min. Length
Meters
SP-1, SPT-1
SJ, SJT
1-1/2
1-1/2
3.0
7.5
SP-2, SPT-2
1-1/2
3.0
SP-2
1-1/2
7.5
TP, TPT
1-1/2
3.0
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B. The length of a power supply cord is to be measured from the face of the attachment-lug cap to
the point where the cord emerges from the appliances.
C. Cord Connector Body  a cord connector body employed as part of a separable cord set shall be
so constructed that the cord-connector body cannot readily be used to defeat the conventional interlock
device.
D. The conventional interlock device referred to above has nominally 2.5 mm. diameter pins,
spaced 8 mm. apart, measured between pin centers.
E. Cord Strain Relief  The power supply cord shall be attached to the appliances so that a
mechanical strain on the cord leaving the overall enclosure will not:
a) Be transmitted to terminals, splices, interior wiring or;
b) Separate an interlock connector from the part of the appliance to which it is attached; or,
c) Damage an interlock so that it does not perform its intended function.
F. Cord Push-Back Relief  The power supply cord shall be provided with a knot or an equivalent
stop which will prevent the cord from being pushed inside the chassis.
G. Cord Bearing Stress  If a knot in a power-supply cord serves as strain relief, the surface
against which the knot may bear or with which it may come in contact shall be free from projections,
sharp edges, burrs, fins, which may cause abrasion of coverings on the conductors.
H. Cord and Wire Routing  A separate flexible cord or wire which is not connected in the supply
circuit or which does not involved shock or fire hazard shall not be routed through a bushing or opening
with the power-supply cord.
I. Bushing  Except as noted in Rules 9.2.3.J and 9.2.3.K, there shall be suitable insulating
bushing, or the equivalent, which shall be substantial and reliably secured in a place where the powersupply cord emerges from the enclosure, and where the cord may be subjected to strain or motion.
J. An insulating bushing is not required with a Type SP-1 cord if the cord is built up with an
additional 40 percent rubber jacket 0.8 mm. thick minimum at the point where it passes through the
metal and if the hole through metal is free from sharp edges, burrs, fins, etc. a smooth metal bushing is
acceptable if the Type SJ or heavier cord is used.
K. A smooth metal grommet is acceptable as a bushing in an enclosure other than metal, provided
the inside diameter of the grommet is not less than 2.5 cm.
L. If the exit for the cord is in wood, porcelain, phenolic composition, or other suitable insulating
material, a surface free of fins, burrs, and the like is considered to be equivalent of a bushing.
M. Ceramic materials and some molded compositions are considered acceptable for insulating
bushings; but separate bushing of wood, rubber, and so-called hot-molded shellac, and tar compositions
are not considered acceptable.
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N. Fiber may be employed if the finished bushing is 1.2 mm. thick minimum and if it is so formed
and secured in place that it will not be affected adversely by conditions of ordinary moisture.
O. Polarized Appliance  An appliance that is provided with a polarized attachment-plug cap of
the two-wire parallel-blade type shall comply with the following:
a) An accessible part of the appliance shall not involve shock hazard.
b) There shall be no hazard with the attachment-plug cap inserted in the supply-circuit receptacle
and then with supply-circuit connections reversed.
c) A switch, circuit breaker, fuse or other protective device shall not be connected in a circuit that
is connected to the wide blade of the attachment-plug cap unless the component will simultaneously
interrupt both conductors of the supply circuit.
d) The breakdown of a capacitor connected to an accessible metal part shall not cause the
accessible part to involve shock hazard.
e) The screw or the equivalent of a lamp-holder shall not involve shock hazard when the lamp is
accessible for servicing.
f) A polarized receptacle of the parallel-slot type mounted on the appliance shall have the
identified (white) terminal connected to the wide blade of the attachment-plug cap.
g) In an interlock connector is mounted on a cover that can be applied as a complete enclosure in
a normal manner but with the interlock connections reversed, the size, shape, or rearrangement of the
contacts shall be such that the connection of the two interlocked parts can be affected only in one
way.
h) Unless proper polarization is ensured by visual inspection and component checking, each
complete appliance shall be treated, as a routine factory test, for electrical continuity between the
wide blade of the attachment-plug cap and the part of the appliance circuit that is intended to be
connected to the wide blade of the attachment-plug cap.
P. Except as required in Rule 9.2.3.O, the conductor of the supply circuit that is connected to the
wide blade if the attachment-plug cap is considered to be at ground potential when evaluating shock
hazard.
9.2.4 Wiring Devices
A. Mounting of Wiring Devices  A switch, lamp holder, attachment-plug, or similar components
shall be mounted securely except as noted in 9.2.4 B and 9.2.4 C.
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B. The requirement that a switch be prevented from turning may be waived if all four of the
following conditions are met:
a) The switch is to be a plunger or other type that does not intend to rotate when operated (a
toggle switch is considered to be subject to forces that tend to turn the switch during the normal
operation of the switch).
b) The means of mounting the switch make it unlikely that operation of the switch will loosen it.
c) The spacing‟s are not to be reduced below the minimum acceptable values if the switch rotates.
d) Normal operation of the switch is to be by mechanical means rather that by direct contact by
persons.
C. A lamp holder of a type in which the lamp cannot be replaced, such as a neon pilot or indicator
light in which the lamp is scaled in by a non-removable jewel, need not to be prevented from turning if
rotation cannot reduce spacing‟s below the minimum acceptable values.
D. A lamp holder designed to be readily removable without the use of a tool need not to be
prevented from turning.
E. The means for preventing the turning mentioned in Rule 9.2 ..A is to consist of more than
friction between surfaces  e.g., if suitable lock washer, properly applied is acceptable as the means of
preventing a small stem-mounted switch or other device having a single-hole mounting means from
turning.
F. Unused Receptacle  An unused receptacle, such as one provided for the attachment of an
accessory, that involves hazardous energy shall not be of the type generally employed as a receptacle
for a single prong, shielded-type phonograph plug, and if of the conventional parallel-type, shall
involve line power only.
G. Receptacle Mounting Clearance  If the face of a receptacle is less than  mm. wide or less
than 22 mm. long, the face of the receptacle shall project not more than 5 mm. from the part of the
mounting surface that is within a rectangle 16 mm. wide and 22 mm. long symmetrically located about
the receptacle contacts and if the mounting surface is conductive, the face of the receptacle shall project
not less than 2.5 mm. from that part of the mounting surface.
H. Receptacle Insertion Clearance
 Except as noted in Rule ...K the area surrounding an
unused attachment-plug receptacle shall be free of any projections which would prevent full insertion of
the blades of a circular attachment-plug cap having a face diameter of 30 mm. unless the projections are
such that the blades of the attachment-plug are prevented from being inserted to make electrical contact
with the female contacts of the receptacle.
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I. Clock-Radio Receptacle  The area surrounding an unused clock-controlled attachment-plug
receptacle in clock radios and the like shall be free of any projections which would prevent full
insertion of the blades of a circular attachment-plug cap having a face diameter of 33 mm. and of a
rectangular cap having a face of 38 mm. by 16 mm., unless the projections are such that the blades of
the attachment-plug cap are prevented from being inserted to make electrical contact with the female
contacts of the receptacle.
J. Lamp holder Construction  The terminals of a lamp holder shall be securely riveted or
otherwise secured in place. The center contact and its mounting shall be so secured that it will be held
within the shell when the lamp is removed. The lamp holder terminals and other live parts, including
the lamp base, shall be so protected that the possibility of grounding or of shock hazard, in use or while
servicing, is remote. Soft rubber shall not be used for the insulation of lamp holder shells.
K. Switch Application  A switch connected to wiring involving fire or shock hazard shall be
suitable for the particular application.
L. Transfer Switch

A transfer switch employed in a combination line and battery-operated
appliance and involving shock hazard shall be so arranged that it cannot be accidentally operated.
M. Clock-Operated Receptacle Switch Enclosure  Clock operated switch contacts controlling an
unused attachment-plug receptacle shall be provided with an enclosure of non-combustible material.
N. Sheet metal 0.35 mm. thick minimum, phenolic composition 2.0 mm. thick minimum, or
asbestos 0.8 mm. thick minimum and not impregnated with a highly flammable compound, may be
used for the non-combustible enclosure required in the preceding paragraph if the assembly is such as to
provide adequate mechanical strength.
O. Clock-Operated Appliance Switch Enclosure  Clock-operated switch contacts controlling only
the appliance shall be provided with an enclosure complying with the requirement for the enclosure of
other parts of the appliance.
P. Clock-Operated Switch Openings  Openings may be provided in the enclosures required in
Rule 9.2.4.M if the enclosure is located within the cabinet of the appliance. The openings shall not be of
such size or number as to permit the propagation of flame out of the enclosure.
Q. Openings may be provided for conductors if the total area of the unused portions of such
openings does not exceed 6.5 sq. mm.
R. Slots 1.2 mm. or less in width may be provided if they are necessary for purposes of assembly.
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S. Other openings may be provided if:
a) They are located not less than 38 mm. from the switch contacts.
b) The total area of the openings is not more than 58 sq. mm.
c) The total area of the openings are less than 7.5 cm. from the switch contacts, is not more than
19.5 sq. mm. and,
d) The distance between the opening and combustible material outside the enclosure is not less
than the smaller dimension of the opening.
9.2.5 Fuses
A. Fuses Marking  A fuse, including a clip-in type, if used to prevent a fire hazard, shall be
marked as described in Rule 10.7.24.
Protective Devices  A protective device, such as a fuse, manual-reset overcurrent device, fusible
resistor, etc., shall be designed for the purposed of overload protection. Rule 10.7.24 (Fuse
Replacement Marking) and Rule 10.7.26 (Protective Devices Replacement Marking).
B. Battery Circuit Fuse  A fuse shall be provided in a circuit designed for use with a storage
battery, or an appliance having a self-contained storage battery if a fire hazard is involved. The fuse
shall be located in or adjacent to the battery connecting means.
C. A marking need not be provided for the fuse holder.
9.2.6 Transformer
A. Coil Impregnation  The coils of transformer shall be impregnated or otherwise enclosed to
exclude moisture.
B. Transformer Enclosure  Except as noted in Rule .. E, transformer wh ich is normally
connected across a supply circuit shall be completely and individually enclosed in noncombustible
material. The enclosure shall not be provided with holes or louver which will allow the circulation of
air, except holes for the entrance of wires. The unused portion of any hole in the enclosure for the loads
to the transformer shall not larger than 1.3 sq. cm. in area and the total unused portion of two or more
holes shall be not larger than 2.3 sq. cm. in area. Any hole provided in the enclosure for lead wires, but
not so used, shall be effectively closed with noncombustible material.
C. A small amount of phenolic composition, such as a terminal block will be acceptable in the
enclosure of a transformer.
D. If a transformer enclosure is appreciably larger than the transformer itself, the acceptability of
the combination is to be investigated.
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E. Transformer Without Enclosure  A transformer need not be provided with an enclosure of
noncombustible material if it has an input of 60 watts or less, measured after one minute of operational
with all secondary windings short circuited, and if it conforms acceptably in the test described in the
following test (Unenclosed Component Abnormal Operation Test).
Unenclosed Component Abnormal Operation Test  A part that is not provided with an enclosure
in accordance with Rule 9.2.15.D. (Component Enclosure), or a part, such, as a motor, which is
connected in the circuit for a limited period during the operation of the appliance but which may be
operated continuously under abnormal conditions shall be tested as follows:
a) A part is subjected to continuous under applicable abnormal conditions for seven hours unless
open-circuiting of the component under test occurs in a shorter time. The supply circuit is fused at 30
amperes. Exposed dead-metal parts of the component under test are connected to ground through a
one-ampere fuse.
There is to be no emission of flame or molten metal, exposure of live parts, opening of the fuse in the
ground wire, nor glowing or flaming of a single layer of cheesecloth placed around the part in
question or its enclosure.
b) The cheesecloth is loosely draped over the enclosure within 3.0 mm. of opening.
c) The part and its circuit, with any included vacuum tubes short-circuited, is mounted as
intended in the overall enclosure and connected to the power-supply circuit.
d) A motor, including one provided with a slip mechanism is installed. The secondary of a motor
transfer is connected to its normal load.
e) The secondary of a motor transformer normally connected across a power-supply circuit
without any series vacuum tubes is short-circuited.
f) Inherent over-heating protection, if provided, is to be investigated to determine its
acceptability.
g) The test circuit is energized continuously for several hours, unless the circuit is opened in a
shorter time by the failure of one of the circuit components. If the circuit is opened by a component,
two additional samples are tested in the same manner.
9.2.7 Capacitors
A. Plug-In Capacitor  A capacitor of the plug-in type shall be so mounted or located that a tool is
required for its removal from the circuit in which it is used.
B. Insulating Capacitor  A capacitor used for antenna blocking. Line by-pass, or metal cabinet
isolation; or between live parts and exposed metal parts where the capacitor is continually stressed,
shall be a recognized type.
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9.2.8 Batteries
A. Battery Connections  A battery of a combination supply circuit and battery-operated appliance
shall not be connected to the supply circuit unless the current-carrying parts are so insulated, arranged,
or otherwise protected that no fire or shock hazard is involved.
B. Battery Terminals  The terminals of a battery shall be protected to prevent accidental shortcircuiting during installation and while in service.
C. Battery Potential  The terminals of a battery having an open-circuit potential of 100 volts or
more shall protected against accidental contact, and the connected wiring shall comply with Rule
9.2.9.A (Wire Insulation).
9.2.9 Wiring
A. Wire Insulation  The insulation on wires which involve fire or shock hazard shall be rated for
the voltages involved and the temperature attained under any condition of actual use, and shall be flame
retardant. The insulation on wires that does not involve fire or shock hazard need not have a flameretardant rating if the wires are segregated (e.g. by routing) from wiring involving fire or shock hazard.
B. Thermoplastic insulated wire with an insulation thickness of 0.4 mm. is suitable for use at
voltages of 600 volts peak or less; 0.8 mm. for voltages of more than 600V but not more than 2500
volts peak and 1.2 mm. for voltages of more than 2500V but not more than 5000 volts peak. The 1.2
mm. thick insulation may be integrally applied or may be built up with insulation 0.8 mm. thick plus a
jacket or recognized sleeving 0.4 mm. thick. Insulated conductors rated at 5, 10, 20, 30, 40 or 50
kilowatts, direct current are suitable for use at voltages not exceeding those ratings. In determining the
suitability of insulated high voltage conductors in a TV set, voltages are measured with the appliance
connected to a 130-volt source of supply and with all controls adjusted to give maximum voltage
possible with a reusable picture.
C. The lead connected between the horizontal output transformer and the plate of the high voltage
rectifier tube may be operated in excess of its voltage rating provided the through-air spacing between
this wire and opposite polarity parts comply with Rule 9.2.9.B. In determining this spacing, the lead is
to be connected and placed in any position permitted by its length.
D. A hook-up wire employing thermoplastic insulation with wall thickness less than 0.4 mm. but
not less than 0.18 is suitable for use at voltages of 300 volts peak or less if the wire is entirely within a
chassis or is protected against mechanical injury are not subject to flaking during normal operation or
handling during user-servicing.
E. For a cable or cord involving voltages of not more than 600 volts peak between conductors or
between any conductor and ground the composite insulation is to be 1.2 mm. thick, or the equivalent,
except that cable assemblies such as jacketed coaxial cables are considered with respect to the intent of
the requirement. A close cotton braid or a paper tape suitable for the forces involved may be employed
to supplement the insulation. Where a metal clamp is used, it is to be free of sharp edges and burrs and
is to have a suitable bearing surface and clamping action to prevent damage by abrasion or cold flow of
the insulation.
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F. Primary Wiring  The primary wiring of a power-transformer-operated appliance (including the
transformer primary winding leads but not the primary winding) having a power-supply input of more
than 300 watts shall be not smaller than No. 18 AWG unless an investigation shows that overloading of
the primary wiring due to faults in the circuit connected to the secondary of the transformer, or in the
transformer itself, will not result in a fire hazard.
G. Small Gauge Wire  Wire smaller than No.  AWG shall be protected against mechanical
injury or shall be suitable for the application, taking into consideration the effects of vibration, impact,
and handling during user-servicing.
H. Wire Handling
 The conductor of a wire involving fire or shock hazard shall not become
exposed due to handling during user-servicing.
I. Remote Cable  Except as noted in Rules ...J, ...K and ...L, a cable used for the
connection of a remote speaker, a remote control, or like shall be Tlpe SJ flexible cord, or the
equivalent. If the cable is permanently attached to the appliance, it shall be provided with a cord exit,
strain relief, and push-back relief as described in Rule 9.2.3 F.
J. Type SV or SP-2 Flexible Cord, or the equivalent may be used for the connection of a remote
speaker, etc., if the length of the cord is limited to 4 meters.
K. Type SP-1 Flexible Cord, or the equivalent may be used for the connection of a remote speaker,
etc., if the length of the cord is limited to 4 meters.
a) The potential between the conductors of the cord and between any conductor and earth or other
accessible part, is to be not more than 45V RMS if the current through a 1500-ohm load connected
between these points is more than 30 milliamperes;
b) The appliance is not to involve a fire hazard when it is subjected to abnormal test involving
short-circuits between conductors of the cord, and between any conductor of the cord and earth or any
other accessible parts.
L. A type of wire or cord other than Type SJ, SV, or SP-1, or their equivalents, may be used for
the connection of a remote speaker etc., under conditions stated in Rule 9.2.9.K, with the added
condition that the arcing test described in Rule 9.2.11 B is not to result in a fire hazard.
M. Low-Energy Circuit Wiring  Low energy circuit wiring, such as an antenna lead, which is
not, housed entirely within the enclosure and which any contact parts therein which involve shock or
fire hazard shall be insulated adequately within the enclosure. Such wiring shall be as described in
Rule 9.2.3.E (Cord Strain Relief), Rule 9.2.3.F (Cord Push-Back Relief) and 9.2.3.G (Cord Bearing).
N. Wiring which is subject to motion, as in the case of a tuning mechanism assembly, is to be
investigated to determine the effect of continued operation under service conditions.
O. Cable Strain or Motion  A cable or cord that is subject to strain or motion during normal
operation shall be provided at all points of strain or constricted motion with suitable insulation
between conductors and adjacent metal parts, if breakdown will result in a shock or fire hazard.
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P. Wiring Subject to Motion  Wiring which involves fire or shock hazard and which connect s
parts subject to servicing, such as a tuning tube or dial lamp, and which is subject to motion, shall be
as described in Rules 9.2.3.E (Cord Strain Relief) and 9.2.3.G (Cord Bearing Surface).
Q. Television Wiring Subject to Handling  A television ap pliance lead involving fire or shock
hazard and which may be flexed or handled during user servicing shall be suitably secured.
R. Opening in Metal  An opening in metal used for the passage of a wire connected to a circuit
involving fire or shock hazard shall be free from sharp edges, burrs, fins, etc.
9.2.10 Insulating Material
A. Live Part Insulating Material
 Material for the mounting of uninsulated live parts which
involve shock or fire hazard shall be phenolic composition, or other equivalent moisture-resistant
material which is suitable for the particular application See Rule 9.2.1.C (Self-Extinguishing Material).
B. Hard fiber may be used for insulating bushings, washers, separators, and barriers, but not as the
sole support for uninsulated live parts where shrinkage, current leakage, or war page may introduced
hazard.
C. Degaussing Coil Insulation  Except as noted in Rule ..0 D insulation on a degaussing coil
involving fire or shock hazard shall be of suitable material having a minimum thickness of 0.7 mm. or
shall withstand the arcing test described in Rule 10.3.15 (Degaussing Coil Insulation Arcing Test).
D. Degaussing Coil Insulation may be 0.33 mm. minimum thick if it is located where it will not
subject to damage or displacement during a factory assembly or user servicing.
E. Guard and Barrier Insulation Material  Except as noted in Rule ..0.F, a guard or barrier of
insulating material employed to render live parts inaccessible shall be 0.7 mm. minimum thick.
F. Fiber, or the equivalent, 0.33 mm. minimum thick may be used to cover a splice in a particularly
protected location. A 0.33 mm. minimum thick covering of paper, waxed or otherwise treated to resist
absorption of moisture may be used for the cross-over lead of a coil winding connected in a circuit
involving shock hazard, in a partially protected location. A covering of paper 0.7 mm. minimum thick,
may be used on an electrolytic capacitor or similar part. A fiber shell of a metal-jacketed pilot lamp
holder covering all live parts may be 0.5 mm. thick.
9.2.11 Conductive Coatings and Shields
A. Conductive Coating  A chassis-connected conductive coating on the inside of a wood cabinet
or a suitable conductive shield shall comply with the test described in Rule 9.2.11 B (Conductive
Coating Arcing Test).
B. Conductive Coating Arcing Test
 A chassis connected conductive coating used to prevent
shock hazard (1) in the event of electrical breakdown to its wood cabinet is lieu of compliance with
Rule 10.1.72 (Accessible Part Dielectric Withstand Test), or (2) in the event of contact between the live
part and cabinet shall withstand arcing between the live part and the coating without causing the
flaming of any material for more than one minute following the arcing.
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C. The arching under condition (1) is to be for 15 minutes. The arcing under condition (2) is to be
for 30 minutes if the contact between live part and the cabinet can be established only as a result of
servicing of the appliance and the appliance is disabled. Contacts resulting from other causes are to be
investigated with respect to the duration of the arcing.
D. The appliance is to be operated under the conditions described in Rules 10.1.78 and 10.1.79. The
arc is to be established between the live part and any part of the conducting coating by the use of a
conductive probe. Current and voltage measurement are taken during a five-minute period following the
arcing test.
E. Conductive Coating Voltage and Current Test  With a connection made between the live part
and any part of the conductive coating mentioned in Rule 9.2.11.B, including the part where arcing
occurred, the voltage measured by an electrostatic voltmeter between the live part and chassis shall not
exceed 1270 volts peak, and the current through a 500 ohm load connected between the live part and
chassis shall not exceed 5 milliamperes.
F. Conductive Shield  A conductive shield or the equivalent shall be located and connected so
that any possible breakdown between the windings, or between the windings and the shield of the
power transformer, will not result in an accessible metal part being energized at more than 1000 volts
peak with respect to ground or the transformer shall comply with rules 9.2.11.G (Power Transformer
High-Voltage Secondary AC Dielectric Withstand Test), and 9.2.11.H (Power Transformer HighVoltage Secondary DC Dielectric Withstand Test). The shield is to be examined to determine that it is
properly arranged and that it will withstand the high-voltage arcing without burning through.
G. Power Transformer High-Voltage Secondary AC Dielectric Withstand Test  Except when a
suitable shield is provided an alternating potential of four times the rated primary voltage at four times
the rated frequency shall be applied across the primary winding that has no connection to the chassis.
The test potential is applied across the primary winding with one end of the winding connected to the
chassis. If a secondary winding has no connection to the chassis, this test shall be made first with one
end of the secondary winding and then the other in turn, connected to the chassis.
H. Power Transformer High-Voltage Secondary  DC Dielectric Withstand Test  Except when a
suitable shield is provided, a direct-current potential of four times the peak potential measured between
the winding of a power transformer and any other winding of the transformer, e.g., a damper tube heater
winding, operating at a potential of more than 1000 volts peak, measured under the conditions
described in Rules 10.1.78 and 10.1.79 with respect to the chassis if electrical breakdown would result
in shock hazard.
9.2.12 Connectors, Component, and Leads.
A. Part Disconnection  The disconnection and displacement of parts resulting from shipping or
moving of the appliance shall not result in a hazard, as described in rules 9.2.12.B (Primary Insulation
Voltage Test) and 9.2.12 C (Component Shock Hazard Test).
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B. Primary Insulation Voltage Test  A high-voltage part that is accessible while energized, or that
is likely to be left in contact with accessible metal, with parts of the power supply circuit, with a
wooden cabinet, or with a similar part having a relative low level of insulation, shall not cause a
breakdown of the primary insulation or develop a voltage of more than 1270 volts peak across primary
insulation when connected to the chassis or earth.
C. Component Shock Hazard Test  To determine if the connectors, components and leads of an
appliance comply with the shock hazard requirement of Rules 9.2.12.A (Part Disconnection), the
appliance is operated under the maximum voltage conditions described in Rules 10.1.78 and 10.1.79.
Current and voltage readings are taken during the initiative five minutes of the test. To determine if the
connectors, components, and leads of an appliance comply with Rule 9.2.12.A. (Part Disconnection)
and with respect to Fire Hazard, the appliance is operated with all controls adjusted for picture
operation. The lead or connector is brought into contact with any part of different potential with which
contact is likely to be established. If the contact results in arcing, the arc is maintained for 15 minutes.
A material that is not recognized as reliable insulation may be considered conductive. A material
located between the lead or connector and the part of different potential in the path of possible electrical
breakdown is subjected to the arcing in order to determine if ignition can be produced. There is to be no
flaming or glowing of any material for more than one minute following the discontinuance of the
arcing. A condition established only a result of user servicing of the appliance and which results in the
disabling of all the intended functions of the appliance is permissible.
D. With respect to shock hazard, a part that is within an enclosure having a cover with a suitable
interlock is not to be considered in its displaced or disconnected condition after the interlocked cover
has been replaced if (1) such displacement or disconnection is obvious prior to replacement of the
interlock cover and (2) an energized accessible part does not involve a potential of more than 150 volts
with respect to ground or any other accessible part.
E. Flaming of any material resulting from user servicing which disables all the intended functions
of the appliance, such as television, radio, record player, etc., is permissible.
F. Barriers, mechanical restraints and the effect of gravity are to be given consideration; but a
fastening means that relies solely on friction between parts is not considered acceptable unless found
suitable for application. A fastening means is not removed if it cannot be removed unintentionally and
need not be removed during user servicing. A flexible fastening means should return to its original
position and shape after flexing.
G. High-voltage Part  A high-voltage part that is likely to be left in contact with accessible metal,
a wooden cabinet, or a similar part having a relatively low level if insulation shall not involve shock
hazard with respect to the chassis assembly or earth.
H. For parts involving 1000 volts peak or more, materials that are not recognized as reliable
insulation may be considered as either conducting or insulating or a combination of both. For parts
involving less than 1000 volts peak, consideration shall be given to the insulating qualities of the
material involved, the voltage involved, and the likelihood of displacement or disconnection.
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9.2.13 Voltage Limiting Means
Spark Gap and Discharge Tube
 A spark gap or a gaseous-discharge tube shall be investigated to
determine its suitability as a current or voltage limiting means.
9.2.14 Current-Carrying and Live Parts
A. Contact Material  Contacts of sockets, separable connectors, and the like, connected in circuits
involving fire hazard shall be made of materials suitable for the application.
B. Live Part Spacing
 A live part shall be spaced or insulated for the voltage involved and
protected for the expected service.
C. Loop Antenna Mounting  An exposed or accessible loop antenna and its terminals, if
conductively connected to the supply circuit involving shock hazard, shall be securely mounted on
insulating material unless the loop antenna conductors are insulated as for wiring connected to the
supply circuit.
D. Accessible Part Shock Hazard
hazard.
 An accessible part of an appliance shall not involve a shock
E. The accessibility of a live part is determined by Table II.
Table 9-2
RECESSING OF LIVE PARTS
M ini mum Width of
Di ameter of Round
Slots-mm.
H oles-mm. (D )
M ini mum Distance
Between Openi ng
And L ive Part a b c
More than 2.4
But not more
than 22
More than 22
but not more
than 50
More than 2.5
but not more
than 25
Probe d, e, f
More than 25
but not more
than 50
5D + X
More than 50
but not more
than 75
6D + X
More than 50
But not more
Than 75
7D + X
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a) D is the diameter of the largest sphere that will pass through the opening.
b) X is 3.2 mm. for each 1000 volts peak or fraction thereof at the live part. The voltage is to be
measured with the appliance connected to a supply circuit as described in Rules 10.1.78 and 10.1.79.
c) If the bottom of a console cabinet is 75 mm. or less from the floor, the amount of recessing is
based on the height of the cabinet bottom above the floor, whenever is the smaller; and the distance is
measured from the edge of the cabinet. If the bottom is more than 75 mm. but not more than 150 mm.
from the floor, the amount recessing is based on the size of the opening in the bottom and the distance
is measured from the plane of the openings.
d) The tapered portion of the probe shall not contact a live port operating at a potential of 1000
volts peak or less.
e) The distance between the part and the tapered portion of the probe shall be no less than 3.2
mm. for each 1000 volts peak or fraction thereof in excess of 1000 volts peak (e.g., 2500 volts peak,
13 mm.)
F. Friction fit knobs, snap covers and similar loose parts are removed or opened when judging
accessibility. No part of the collar should enter the opening during measurement.
G. A part is not considered accessible if it is located behind an opening having a dimension of 2.4
mm. or less or within an enclosure having a cover that cannot be opened by a child and that is not likely
to be opened or removed during normal operation or user servicing.
H. A part beyond an opening that may be used in making an adjustment which is considered a
function of user servicing is not considered a function of user servicing is not considered to be
accessible if a 3.2 mm. diameter straight rod is prevented from touching the part when the rod is
inserted through the opening and moved to all positions possible without producing an angle of more
than 30 degrees between the rod and a line drawn between the center of the opening and the center of
the face of the adjusting mechanism. The length of the rod beyond the opening is not to exceed the
distance between the opening and the face of the adjusting mechanism by more than 8cm.
I. Protective screens or barriers, openings larger than those covered in Table II, irregular openings,
and openings in flexible materials are to be given consideration with respect to the intent of the
requirements.
J. Live parts are to be inaccessible after chassis-mounting hardwares are loosened during
installation as intended to reduce vibration. Chassis mounting bolts not specifically designed to prevent
further loosening except by the use of a tool, are to be loosened the maximum amount likely to occur in
service in determining the inaccessibility of live parts.
K. Control Shaft Shock Hazard  A control shaft which involves shock hazard shall be rendered
inaccessible by means of a suitable interlocked compartment of by means of an insulating knob which
is not removable from the exterior of the enclosure.
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L. Set screws, sealing compound, or devices which depend upon friction to prevent removal of a
knob from the exterior of the enclosure are not considered acceptable.
M. Captive Part  A pa rt of the appliance (1) that is subject to removal during user servicing, (2)
that is not essential for the functioning of the appliance, (3) that is not exposed to view during normal
use, and (4) the omission of which may produce a hazard, shall be made captive or otherwise arranged
to ensure its use.
N. User Servicing Guard

A guard to prevent access to live parts through openings in an
interlocked enclosure shall be hinged or otherwise prevented from being discarded if it must be
removed from user servicing. The guard shall not be rendered ineffective without being intentionally
deformed or obviously misplaced.
O. Top Opening  Except as noted in Rules ...Q and ...R, an opening in the top of the
overall enclosure shall not permit the passage of a sphere of more than 2.4 mm. in diameter if the
passage of an object through the opening results in a shock hazard.
P. The top of the overall enclosure is considered that portion of the enclosure that is visible in plain
view when the appliance is resting on a horizontal surface, with all drawers and lids closed except a lid
that must be detached for operation. Push buttons are to be in maximum displaced position that the
construction permits.
Q. An opening in the surface which makes an angle of 30 degrees or more with the horizontal is
considered acceptable if the projection of D onto a horizontal plane does not exceed 2.4 mm. when
measured in the direction of the maximum slop of the surface in which the opening is located. The
upper edge of the opening is the point of tangency between a vertical line and the enclosure above the
opening. The lower edge of the opening is the point of tangency between the enclosures at an angle of
five degrees to the horizontal.
R. An opening having a dimension larger than 2.4 mm. and protected by a knob, handle, louver, or
similar part is accepted by a knob, handle, louver, or similar part is acceptable if a falling object cannot
pass directly through the opening in a vertical direction and if the construction is such that an object
placed at any point on the enclosure will not slide or roll into the opening. This will generally require a
1.6 mm. lip on the surface surrounding the opening. A knob protecting an opening is to be in its shaft as
far as possible without rubbing on the enclosure.
S. Octal Base Tube Socket Shock Hazard  An octal-base tube shall have its pin contacts recessed
1.5 mm. and shall prevent contact between a pin connected to any accessible metal part of a tube and
socket contacts which involve shock hazard.
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T. Interlock  A interlock to eliminate shock hazard shall be so constructed and installed so that it
is substantial, reliable and complies with one of the following:
a) The interlock device be such that it cannot be defeated readily without:
1) Damaging the appliance
2) Making wiring connections or alterations
3) Using other than ordinary tools, or
4) Using materials other than those readily available. Adhesive tape, string or conventional
extension cord sets are considered readily available.
If two momentary contact switches must be operated to energized the appliance, the arrangement
shall comply with (4) above and the operating means shall be spaced from each other and from live part
so that if they are operated simultaneously by one individual, contact with live parts shall be unlikely.
b) The interlock device of an appliance shall be such, that during normal operation and user
servicing.
1) The interlock is not likely to be defeated by improper disassembly, e.g., removal of the
wrong screws, removal of the cover;
2) The cover in which the interlock is mounted shall not be rotated by its own weight about the
interlock axis perpendicular to the cover during any stage of its removal or replacement, if such
rotation gives access to a live part, or damages the interlock or the cover;
3) The act of removal or replacement of the interlocked cover shall not subject the user to
unintentional contact with live parts;
4) The interlocked cover cannot be readily misapplied to result in shock hazard, unless such
misapplication is obvious during and after replacement of the cover; and
5) The appliance shall be marked as follows:
INTERLOCK
WARNING 
AN APPLIANCE THAT INCORPORATES AN
INTERLOCK DEVICE COMPLYING WITH ITEM (B) OF RULE 9.2.14 T (INTERLOCK
SHALL BE MARKED WHERE IT WILL BE READILY VISIBLE DURING ANY
APPROACH TO DEFEAT THE INTERLOCK, WITH (1) A STATEMENT THAT AN
INTERLOCK IS PROVIDED TO PREVENT DANGEROUS ELECTRICAL SHOCK,
WITH THE GENERAL LOCATION OF THE INTERLOCK INDICATED, (2) A
WARNING AGAINTS DEFEATING THE INTERLOCK, AND (3) STATEMENT THAT
THE COVER SHALL BE REMOVED FOR SERVICING.
U. Parts that are recessed more than 63.5 mm. from the edge of the cabinet opening, normally in the
plane of the cover, are excluded when determining that the act of removal or replacement of a cover
will subject the user to unintentional contact with live parts.
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V. If it is necessary to remove a chassis from the cabinet for user servicing, the arrangement of the
interlock assembly would not be readily defeatable with the chassis out of the cabinet.
9.2.15 Enclosures
A. Mechanical Protection  An appliance shall be provided with a cabinet or equivalent enclosure
which shall house all live or current-carrying parts, other than cords or cables. The enclosure shall be
substantial and shall protect the various parts of the appliance against mechanical injury, except for the
vacuum tubes of tuners, tuner-amplifiers, and amplifiers intended for protected installation in home
systems.
B. Corrosion Protection
 The corrosion protection of a metal enclosure shall be paint, terne
coating, zinc chromates, or the equivalent unless the metal is corrosion resistant.
C. Glass Dial Window  A glass window that covers live parts shall be of tempered glass . mm.
minimum thick, or shall withstand the impact test in Rules 10.5.1.H or 10.5.1.N, whenever is
applicable.
D. Component Enclosure  Except as noted in Rule ..5.E, a component such as a capacitor,
inductor, motor, or resistor involving fire hazard shall be housed in an enclosure complying with one of
the following:
a) A complete enclosure of noncombustible material:
1) Molded phenolic and similar composition 3 mm. minimum thick are considered to be noncombustible material for enclosing a chassis whose volume does not exceed 32.78 cu.cm. exclusive
of cans or compartments attached to the chassis. Other plastics and a cabinet housing larger chassis
shall be investigated with respect to rigidity, flammability, deformation at elevated temperature, etc.
Phenolic composition, rubber, and fiber are acceptable for small parts such as bushings and
washers.
2) Sheet Metal 0.3556 mm. minimum thick or asbestos, 0.8 mm. minimum thick and not
impregnated with a highly flammable compound, may be used for a noncombustible enclosure if
the assembly is such as to provide adequate mechanical strength.
b) A metal chassis in which openings shall be of such size and/or number that flame will not be
propagated out of the overall enclosure.
1) Unused openings may be provided if none exceed 4.8 mm. diameter or equivalent area, and
the total area of such openings does not exceed 0.975 sq. cm. within any area which can covered by
a square 5 cm. on each side, and the total area of such openings in the entire chassis does not
exceed 9.75 sq. cm. except that the area limitation does not apply to openings 1.6 mm. or less in
width between the enclosure and the bottom or end of the chassis. In these determinations, the
surface of the chassis is considered as developed into one plane.
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2) Openings may be provided for conductors if they are kept as small in size and as few in
number as practicable. For example, holes of 4 mm., 6.35 mm., 6.75 mm. and 7.15 mm. diameter
should be sufficient for one, two, three, and four 2.54 mm. diameter conductors, respectively. Holes
of larger diameter may be used where necessary, provided that the excess area is included in the
unused opening area mentioned in (1) above.
3) Openings provided for circuit adjustments shall not exceed 7 mm. in diameter or equivalent
area. It is recommended that a circuit-adjusting crew be located not more than 6.5 mm. back of the
opening.
4) Unused openings other than those mentioned above shall not be larger than necessary for the
particular application.
5) An enclosure as described in (a) above having a wood base shall have a gross volume of not
more than 32.75 cu. Meter and the base shall consist of a single sheet of solid wood or plywood 9.5
mm. thick minimum, without openings, and located in an approximately horizontal position beneath
the chassis.
E. Components that need not comply with the requirements of Rule 9.2.15.D:
a) Those which will withstand the test described Rule 10.2.23 (Unenclosed Component Abnormal
Operation Test).
b) A component part connected between the supply circuit and accessible metal part of the
appliance that in not likely to be connected to earth may be housed in an enclosure of a material
having a flammability characteristics comparable to 2 mm. thick polystyrene or 0.7 mm. thick fiber.
c) A component part of a receiver circuit connected across the supply circuit through a suitable
protective device may be enclosed in a material having flammability characteristics comparable to 2
mm. thick polystyrene or 0.7 mm. thick fiber.
d) A capacitor, inductor, or resistor connected across the supply circuit need not comply with
Rule 10.2.23 (Unenclosed Component Abnormal Operation Test) when:
1) The capacitor, inductor, or resistor is in a conventional chassis employing a direct-connected
power supply and rated at 60 watts or less.
2) The capacitor or resistor is connected across the supply circuit through either a vacuum-tube
rectifier or a selenium rectifier with a suitable series resistor.
3) The nominal rating of the rectifier unit does exceed 150 milliamperes, and
4) Except for a layer-wound output transformer, the capacitor, inductor, or resistor is within a
compartment of metal, wood 9.5 mm. thick minimum or phenolic composition 3.2 mm. thick
minimum.
e) A resistor in a secondary circuit of a transformer operated appliance having a power supply
input of less than 300 watts.
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f) A capacitor which complies with Rule 10.2.20 D (Capacitor Flame Test).
g) The usual type of variable capacitor with its air dielectric and small amount of combustible
material.
F. Radio Thermoplastic Enclosure 
A thermoplastic enclosure employed as the sole closure of
live parts shall comply with the test and construction requirements of one option outlined by Table III.
G. The requirements in Table III. for a periodical section do not apply if removal of the section
does not result in a shock hazard. A mechanically weak material or construction, such as a speaker
cone, is not considered a suitable barrier.
Table 9-3
RADIO THERMOPLASTIC ENCLOSURE TEST OPTIONS
One option consisting of all items marked “X” in a vertical column, is considered to satisfy the test and
construction requirements related to all the provisions mentioned.
Test or Constru ction
Test Opti ons
1 2 34 5 6
X X X X XX
Requirements
Enclosure Loading
&
Enclosure Pressure
Enclosure Thickness 3 mm.
min.
X X X X XX
   X X X
Openings and perforated section, such as
a speaker grill, shall not be more than 50%
of the area of the section. Solid portions
of such a section having a width of less
than 3.2 mm. shall be considered
as openings
Material with an Izod notched impact
strength of 2.0 ft.-lb. minimum per inch
or notch for a 3.2 mm. bar-ASTM Test
Method D256-56.
1.5 ft.-lb. impact test-rule
5 ft.-lb. impact test-rule
60° temperature stability test, appliance
operating rule
90°C circulating air oven test, appliance
inoperative rule
95°C circulating air oven test, appliance
inoperative rule
X  X 
 X  
 
 
X   X  
 X   X 

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H. Picture Tube Enclosure Opening  To protect against implosion hazard from a picture tube
having a minimum diameter of 150 mm. or more equivalent face area, the projected area of any opening
in the top, back, sides of front of the enclosure onto a plane perpendicular to a line passing through the
center of the opening and any point on the central axis of the bulb section of the picture tube, shall not
exceed 1.3 cu. cm. unless the minor dimension of the projected area is not more than 9.5 mm.
I. The use of a metal-cone picture tube and the presence of barriers are given consideration in
applying Rule 9.2.15.H.
J. Picture Tube Window Screws  Screws holding a picture tube window in place that thread into
wood and are removable from the outside of the overall enclosure shall penetrate the wood 9 mm.
minimum at a maximum angle of 45 degrees between the axis of the screw and the plane of the
window.
K. Picture Tube Neck Protection  A picture tube neck, socket, and leads shall have an enclosure
or the equivalent that will protect them from mechanical damage from the top and sides.
L. When a guard is used to comply with Rule 9.2.15.K, the projections of the guard onto horizontal
and vertical planes parallel to the axis of the picture tube are to encompass the projections of the
picture-tube neck socket, and leads onto these planes; and an opening in the top of sides of the guard,
having a minor dimensions of more than 13 mm. is to have a maximum area of 6.5 sq. cm.
M. Picture Tube Enclosure  Except for a picture tube having a maximum diameter of less than 5
cm. or equivalent face area, the enclosure for a picture tube shall be constructed so that no material will
be expelled with excessive force when the tube is imploded within the enclosure by a means which does
not impair the integrity of the enclosure.
N. The picture tube and window combination in Table IV are considered to comply with Rule
9.2.15M, if the window is reliably mounted and of the material and thickness indicated.
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Table 9-4
PICTURE TUBE WINDOWS
Pictur e tube
F lat Glass Wi ndow Thi ckness
(M in us Tolerance of 1/64 in ch)
Metal, rectangular face,
maximum face diagonal
43 cm. or less
less
5.5 mm.
laminated glass or
5.5 mm.
tempered glass
All glass, rectangular face,
maximum face diagonal
48 cm. or less
less
5.5 mm.
laminated glass or
5.5 mm.
tempered glass
All-glass, rectangular face,
Maximum face diagonal
53.5 cm. or less
less
6.5 mm.
laminated glass or
6.5 mm.
tempered glass
All-glass, rectangular face,
maximum face diagonal
58.5 cm. or less
less
6.5 mm.
laminated glass or
7 mm.
tempered glass
O. High-voltage Component General
 A combustible part of a component in a high-voltage
circuit and associated parts involving a potential of more than 2500 volts peak shall:
a) Be self-extinguishing as determined by the test describe in Rule 10.2.21 through 10.2.23 and
b) Either
1) Be within an enclosure complying with Rule 9.2.15.P (High Voltage Component Enclosure)
2) Comply with Rule 10.2.15 (High Voltage Arcing Test).
P. High Voltage Component Enclosure

The high-voltage component enclosure shall be as
follows:
a) The top, sides and bottom of the enclosure shall comply with Rule 10.2.20.C (Noncombustible
Part Flame Test), or be of steel 0.36 mm. thick, except that areas without openings may be of steel
0.254 mm. minimum thick.
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b) Except for lead openings in item (d), any opening in the top or sides of the enclosure above the
horizontal plane through the lowest points on the combustible part of a component shall have a
maximum area of 0.19 sq. cm. if the minor dimensions of the openings above the horizontal plane
through the lowest point of the combustible part shall not exceed 25 percent of the total area of the
surface of the enclosure above the horizontal plane; and the total area of the openings within any area
which can be covered by a 2.5 cm. square shall not exceed 2.6 sq. cm.
c) Except for the lead openings in item (e), any opening in the sides of the enclosure below the
horizontal plane through the lowest point of the combustible part of a component shall have a minor
dimension of not more than 6.5 mm. The total area of the openings within any area which can be
covered by a 2.5 cm. square shall not exceed 3.25 sq. cm.
d) In addition to the openings covered by items (b) and (c), two openings 9.5 mm. or smaller may
be provided in the enclosure for the passage of high voltage leads. No more than one lead is to pass
through each hole. These openings are disregarded in determining the total area of openings. The
openings are to be free of sharp edges, burrs, fins, etc. or are to be provided with an insulating
bushing as described in item (f).
e) An opening in the bottom of the enclosure, in the area directly below the combustible part of a
component or within 2.5 cm. of that area in any horizontal direction, shall be protected by a suitable
barrier:
1) The space directly below the opening and for a horizontal distance of 2.5 cm. in all
directions, shall be free of combustible material and
2) There shall be a second bottom complying with item (a) directly under the opening,
extending not less than 2.5 cm. horizontally in all directions from the projected area of the opening
onto the second bottom. Unless protected by a suitable barrier, an opening in the second bottom
shall not be located in the area directly below the enclosures opening or within 2.5 mm. of that area
in any horizontal direction.
f) An insulation bushing in the enclosure shall comply with Rule 10.2.20.C (Noncombustible Part
Flame Test).
g) If there is an opening in the top or side of the enclosure above the horizontal plane through the
lowest point on the combustible part of a component, the space outside of the enclosure shall be free
of combustible material for a distance of 12.5 cm. above the openings, and for a horizontal distance of
2.5 cm. in all directions from the openings.
h) If the enclosure is a large compartment such as a chassis that complies with the foregoing
except for side walls, the space surrounding the combustible part shall be free of combustible material
for a horizontal distance of 5 cm. or more; and the space between combustible part and the top and
bottom of the compartment, including a 5 cm. horizontal distance in all direction, shall be free of
combustible material.
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i) If the enclosure must be opened for user-servicing, its cover shall be hinged or otherwise
prevented from being discarded. The enclosure shall not be rendered ineffective unless it is
intentionally deformed or obviously misplaced.
j) Barriers are considered in applying items (a)-(i).
Q. In applying Rule 9.2.15.O. (High Vol tage Component General) part is considered noncombustible if it complies with Rule 10.2.20.C. (Non-Combustible Part Flame Test), and a lead is
considered non-combustible if it has a flame-retardant rating.
R. Accessible metal parts are those near high-voltage components of the appliance such as cabinets,
masks, escutcheons and panels.
S. The conductive path required in Rule 9.2.15.R need not be provided if the test described in Rule
10.1.83 (High Voltage System Dielectric Withstand Test), does not result in (1) an electrical breakdown
that will produce a permanent shock hazard, or (2) a voltage or more than 1270 volts peak between the
accessible metal part and the part in question unless the arrangement of parts and their insulation are
adequate for the higher measured voltage.
9.2.16 Accessories
A. Accessory Installation Procedure

The installation or connection of an accessory that is
intended to be installed by the user shall not require the use of other than ordinary tools and shall not
require any act that may involve a hazard, e.g., reduction of spacing, damage to components, or removal
of picture tube.
B. Accessory Jumper Plug  If the use of a tool to remove a jumper plug provided in a receptacle
intended for a connection of an accessory involves shock hazard, the plug shall be of such size and
shape that it can be removed readily by hand.
C. Accessory Connection

A receptacle or connector, except as noted in Rules 0.. and
10.1.22, shall be a female type which requires that the accessory/connector have all contacts exposed.
The receptacle or connector shall not involve hazardous energy under normal operating conditions, or
under conditions which may include the introduction of any one short circuit or any one open circuit in
any one component that is not recognized as being reliable, e.g., a vacuum tube, and the connection of
any connector terminal to the chassis to ground, or to any other accessible.
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X. TEST PERFORMANCE
10.1 GENERAL
10.2 FIRE HAZARD LIMIT
10.3 ABNORMAL OPERATION
10.4 STRAIN RELIEF CONNECTORS
10.5 STRENGTH OF ENCLOSURE
10.5.1 Mechanical Test
10.6 TEST METHOD
10.6.1 Implosion
10.6.2 Impact
10.6.3 Bending
10.6.4 Temperature Stability
10.6.5 Test by Manufacturer
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SECTION X
TEST PERFORMANCE
10.1 GENERAL
10.1.1 Values of Voltage and Current are root-mean-square values, unless otherwise stated.
10.1.2 An appliance having both alternating-current and direct-current ratings is tested with appliance
connected to an alternating-current supply and again to direct-current supply, unless it can be established
that one test will result in the maximum operating conditions.
10.1.3 Voltmeters – Unless otherwise indicated, voltage measurements shall be made with a
voltmeter having a resistance of 2000 ohms per volt minimum for potential of 1000 volts or less and
20,000 ohms per volt for minimum potentials of more than 1000 volts.
10.1.4 A lead, connector, or component that is accessible during normal operation or user-servicing is
to be connected for normal operation and is to be arranged in any position likely after user-servicing.
10.1.5 Cheesecloth Indicators – Cheesecloth used for test shall be untreated cotton cloth 9.2 meters
wide, running 29-31 meters per kilogram.
10.1.6 Tests involving cheesecloth are made in a room free of drafts
10.1.7 Supply Circuit Voltage and Frequency – All operational tests shall be conducted with the
appliance connected to a supply circuit of rated frequency and the voltage indicated in the Table
Table 10-1
OPERATING TEST VOLTAGES
Test
Marked Voltage Rating
Normal Operation
105-130
X-Radiation
210-260
Abnormal Operation
Enclosure Temperature
Stability
105-130
210-260
105-130
210-260
105-130
210-160
a
Test Voltage
Maximum marked voltage
but not less than 120 volts
Maximum marked voltage
but not less than 240 volts
130a
260a
130a,b
260a,b
a
130
a
260
For a dual-rated appliance (e.g. 120 volts-230 volts), the test voltage is to be 130volts for the lower
voltage, and 110 percent of the higher voltage, but not less than 240 volts nor more than 260 volts.
b
The test voltage may be reduced to a lower value, but not less than 105 volts or 210 volts, respectively.
The lower test voltage value will represent a more severe condition or in case where a higher voltage
would cause a protective device to open the circuit.
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10.1.8 Power Input Test – The power input shall not exceed the marked input rating by more than five
percent when the appliance is operated with controls adjusted within the range of normal operation of the
appliance so as to produce maximum power input unless the power consumption is not affected
otherwise.
10.1.9 An appliance having its power input affected by signal input is operated with 1000 Hz
sinewave input, with all volume and tone controls adjusted to give maximum output. A matched noninductive load impedance is connected across the output of the appliance, and speakers, if provided, are
disconnected. The input signal voltage is adjusted so that the appliance will produce an audio output
power equal to one tenth the maximum available undistorted sinewave output power, but not less than ½
watt per channel.
10.1.10 a phonograph not having a separate audio-input terminals is operated with the 1000 Hz signal
applied to the first audio stage of the appliance or to the phonograph pick up leads (with the cartridge
disconnected).
10.1.11 A radio or television receiver, or tuner/amplifier will be operated with the 1000 Hz signal
applied to the first audio stage of the appliance.
10.1.12 The maximum available undistorted sinewave power is considered as the maximum
obtainable with no evidence of clipping or flattening of the output sinewave as determined by an
oscilloscope.
10.1.13 X-RADIATION TEST – THE X-RADIATION OF AN APPLIANCE WHEN MEASURED
AS DESCRIBED IN RULE 10.1.14 SHALL NOT EXCEED A DOSE RATE, AVERAGED OVER AN
AREA OF 10 SQUARE CENTIMETERS FROM THE OUTER SPACE OF THE OVERALL
ENCLOSURE OF THE APPLIANCE.
10.1.14 X-radiation measurements are to be made with suitable instruments, under the following
conditions:
(A) The appliance is complete, except that mechanical parts that need to be removed during userservicing may be omitted if they are(1) not necessary for the functioning of the appliance, (2) not
exposed to view during normal operation, and (3) not held captive like a chain, loose rivet, etc;
(B) The voltage of the supply circuit is 130 volts if the rating of the appliance is within the range
105-130 volts, and 260 if the rating of the appliance is within the range 210-260 volts;
(C) After measurements have been made with the supply voltage specified in item (b), the supply
voltage is adjusted to any other voltage within the mentioned ranges that results in greater X-radiation;
(D) all user adjustments (see items (G) and (H) Rule 9.2.2 are positioned to cause maximum Xradiation during appliance operation with sound volume at any level including no sound, and usable
picture that (1) is in synchronization (2) presents viewable although perhaps poor quality intelligence,
and (3) fills the viewing area.
(E) In addition to the adjustments described in item (D), all controls, regardless of location, are
adjusted for maximum X-radiation during appliance operation with sound volume at any level,
including no sound, and usable picture.
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(F) Unless they have been investigated and found to be reliable, a rectifier, tube, protective device
(fuse, circuit breakers, etc;) electrolytic capacitor, transistor, or other solid state device is disabled
singly (short-circuited for electrolytic capacitor, opened for protected device and short-circuited or
opened for others) unless disabling the components does not permit operation with a usable picture.
(G) For a multiple-function appliance, measurements are made with the appliance in any mode of
normal operation, such as one with a video tape playback unit operating at any one of its speed that will
produce a usable picture.
(H) When measuring X-radiation, picture information is injected into the appliance through the
antenna terminals by means of a suitable signal generator. The picture display is to be an “Indian Head”
or equivalent test pattern.
10.1.15 X-Radiation Under Servicing Conditions Test – Unless there is a suitable marking to warn
service personnel of the potential X-radiation hazard, the appliance shall comply with the Rule 10.1.13
(X-radiation Test) under all conditions of a serviceman‟s servicing. See Rule 0.. (X -radiation Under
Servicing Conditions Marking). Serviceman‟s servicing include the removal of shields, windows, cages,
covers with or without the chasis removed from its enclosure.
10.1.15 A Temperature Test – An appliance, when tested under the conditions described below shall
not attain a temperature at any part sufficiently high to constitute a fire hazard, or to affect injuriously any
materials employed, nor to show temperature at specific points greater than those indicated in Table VI.
10.1.16 The appliance is operated until constant temperature are reached (1) at the power input as
described in Rule 10.1.8 (Power Input Test), and (2) with all unused receptacles at their maximum rating,
and (3) enclosured or closed described in Rules 10.1.18, 10.1.19, 10.1.20, 10.1.21.
TABLE VI
MAXIMUM ACCEPTABLE TEMPERATURES
Degrees
Celsius
Materials and Components
Conductors with rubber or thermoplastic insulation
Rubber stain-relief bushing
An electrolytic capacitor b
A cabinet of thermoplastic material a
A selenium rectifier a
Varnished cloth
Fiber
Wood or other combustible material
Fuses
A silicon rectifier a,d
Exterior surface of an overall enclosure
Coil winding surface employing impregnated organic
Insulation or enameled wire
a
Laminated phenolic composition
a
Phenolic Composition
Softening point of any sealing compound
123
60
60
65
65
65
85
90
90
90
100
90
90
125
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a
This lamination does not apply to an insulated conductor, a rectifier, or a material, which has been
investigated and recognized for a higher temperature.
b
A capacitor operating at a temperature higher than 5 C may be judged on the basis of its marked
temperature rating or, if not marked with a temperature rating, may be investigated to determine its
suitability at the higher temperature.
c
A “hot-spot” temperature not higher than 05C on the surface of a coil winding will be acceptable,
provided the temperature of the winding as measured by the resistance method does not exceed 00C. the
temperature limits of 0 C by the thermocouple method and 00 C by the resistance method are based on
the standardized allowance for a maximum “hot spot” temperature at 05 C
 .
d
A rectifier operating at a temperature higher than 00C may be judged on the basis of its case
temperature at the actual current compared with the case temperature at rated current (derating curves).
The temperatures given are based on a room temperature of 5 C. tests may be made at any room
temperature between 0 C and 0 C and the observed temperature corrected for a room temperature of
5 C
 .
10.1.17 Temperatures are measured by thermocouple of No. 28-32 AWG wire. A temperature is
considered to be constant when three successive readings taken at 15 minutes intervals indicate no
change.
10.1.18 The appliance is tested with the maximum projection on the back in contact with a flat
vertical wall of wood or comparable heat-insulating material, except that the spacing between the wall
and the main surface of the back of the appliance should not be less than one inch. Covers likely to be
closed during operation are closed for the duration of the test. Consideration is given to the actual
conditions of normal operation including the changing of records, rewinding of tapes, etc. Record-album
compartments are to be filled to present normal conditions.
10.1.19 Rubber-like and felt materials are removed from supporting feet to the extent that they are
likely to be worn off in normal service. Horizontal ventilating screens subject to the accumulation of dust
and having holes less than 1.2 mm in diameter are to be covered with loose cotton.
10.1.20 An amplifier, tuner or amplifier-tuner, without cover, intended for protected installation in
home systems is to be provided a build-up wood cover stimulating installation in a cabinet. The cover is
to be constructed of wood normally 19mm thick and is consists of a top, sides and front arranged to
exposed user controls. The cover is to provide a clearance of 5cm from each side of the chassis and is to
clear the top of the tallest component part mounted above the chassis by 5cm. in determining the chassis
dimensions, extended flanges and feet are disregarded.
10.1.21 A turntable record changer, or tape deck, without enclosure intended for protected installation
in home systems is to be mounted in a built-up enclosure simulating installation in a cabinet. The
enclosure is constructed on wood nominally 19mm thick and is to consist of four sides and a bottom. The
enclosure is to provide a clearance of 25mm from the bottom of the lowest component.
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10.1.22 The temperature on a winding is measured by applying a thermocouple to the hottest part of
the surface of the coil winding. If the winding is enclosed, a hole is to be made in the case; and if the unit
is potted, a heated wire may be used to provide a hole in the compound before the thermocouple is placed
in contact with the soil surface.
10.1.23 The temperature of a copper winding is determined by the resistance method by comparing
the resistance of the winding at the temperature determined with the resistance at a known temperature
according to the formula.

Where:


(234.5+t) – 234.5
t = The known temperature in degrees C
r = The resistance at the known temperature in ohms
R = The resistance at the temperature to be determined in ohms
T = The temperature to be determined in degree C.
10.1.24 appliance Shock Hazard Current – The available current between exposed or accessible parts
and between such parts and ground shall not be more that the specified in Rule 9.2.1
10.1.25 Interconnection Shock Hazard – The available steady-state current between exposed or
accessible parts, and between such parts and ground, shall not be more than 2-1/2 milliampheres if the
appliance, and if the interconnection can cause an increase in the stock hazard current.
10.1.26 External Antenna Shock Hazard – The available steady-state current between ground and any
one set of external antenna terminals of an appliance shall not be more than one milliamphere.
10.1.27 Potentials are to be measured with a suitable Hi-Z EVM diode vacuum tube meter, and peak
values for AC. + DC potential are to be taken. Steady-state currents are to be measured by means of a HiZ EVM diode-vacuum tube meter or the equivalent and the AC values taken as 0.707 of the peak.
a) For current, the reading is in milliamperes (rms of a sinewave or 0.707 times the peak of a
complex wave).
b) For potential in volts, multiply the reading by 2.12. This produces a value equal to the peak
voltage of a sinewave or complex wave. If the potential measured is limited by a series impedance
within the appliance, the readings of the meter is less than the open-circuit voltage; but under this
condition, the impedance also limits the current leakage. As the series impedance approaches a
capacitive reactance e.g. as the parallel resistance component of the impedance becomes large  the
AC + DC reading becomes less than the AC reading but under this condition, the AC reading is a
suitable measure of the open-circuit voltage.
For AC only  the meter reading are the same as a and b. If different readings are obtained using
both position of the reversing switch, the average of the two reading is to be taken.
For DC only 
C  For current in milliamperes, multiply the reading by 1.414.
D  For potential in volts, multiply the reading by ..
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10.1.28 Current Measurement as made with the attachment plug cap on the supply cord inserted in the
supply circuit receptacle in one position and with the supply circuit condition to the receptacle reversed. If
the appliance has a direct-current rating measurements are made with the appliance connections in turn to
each side of a three-wire, direct current supply circuit.
10.1.29 Current Measurement are made with all parts connected to gather are likely to be contacted
simultaneously by a person during normal operation or user-servicing. Unreliable insulation such as that
usually used between the voice coil and the frame of a speaker, between live parts and the metal frame of
a photograph pickup cartridge and between the two channels of a stereophonic photographic pickup
cartridge is short-circuited during the test.
10.1.30 Current measurements are made (1) with any operation control, or adjustable control that is
considered subject to user operation, in all possible position of contact, and (2) either with or without
tubes, separable connectors, and similar devices in place.
10.1.31 Tube Interchange – The insertion in any socket of any tube or its glass or metal equivalent of
like designation used in the receiver shall not result in a shock hazard.
10.1.32 Consideration will be given to the prospective development of octal base tubes. In most
applications, this will mean that the No.1 contact of any octal base socket is not to be connected to a
circuit involving sufficient potential and current to be classified as shock hazard, unless no metal tubes
are employed and it is not likely that metal counterparts with the No. 1 pin connected to the shell will be
developed.
10.1.34 External Antenna Gaseous-Discharge Tube Test – if a gaseous-discharge tube, or an
equivalent device, is in the circuit between a part involving shock hazard and a terminal provided for the
connection of an external antenna, a direct-current potential of sufficient value to cause breakdown in the
gaseous-tube, or equivalent device, shall be applied across the device. The potential shall then be
decreased to a value of 1.5V +200 volts, at which time the circuit shall not pass a current of more than 5
milliamperes. The construction of a device having a hermetic seal shall be such that device will also
comply with this requirement if a leak occur in the seal.
10.1.35 V is the maximum peak voltage measured between the part involving shock hazard and earth
or an accessible metal part, with the appliance operated under the maximum voltage conditions described
in Rules 10.1.42 and 10.1.43 or 10.1.78 and 10.1.79 whichever is applicable. Voltage measurements are
to be made with the attachmen-plug cap on the supply cord inserted in the supply-circuit receptacle in one
position and then with the cap reversed.
10.1.36 The test is made using three samples of the gaseous-discharge tube or other device. The test
potential is obtained from a high impedance source, the impedance and output voltage of which can be
varied. During the test , the values of impedance and voltage are to be such that the device will not be
damaged by excessive current.
10.1.37 Audio-Output Shock Hazard Test – The audio output potential of an amplifier having
provision for connection of external speaker shall be 100 V or less when tested as described below.
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10.1.38 A variable-frequency signal generator is connected to the input terminals, and a matched load
impedance is connected across the output terminals. The input signal voltage is adjusted to such a value
that maximum available undistorted sinewave power is delivered to the load. The output circuit is then
opened and the potential across the output terminals measured. The test is repeated over the range from 60
to 100 Hz, in steps of 10 Hz, by adjustment of the signal generator.
10.1.39 Primary Insulation Voltage Test – a high voltage part that is accessible while energized, or
that is likely to be left in contact, with accessible metal, with parts of the power supply circuit, with a
wooden cabinet, or with a similar part having a relatively low level of insulation, shall not cause a
breakdown of the primary insulation or develop a voltage of more than 1270 volts peak across primary
insulation, when connected to the chassis or earth.
10.1.40 Component Shock Hazard Test – To determine if the connectors, components and leads of an
appliance comply with the shock hazard requirements of Rule 9.2.12 (Part Disconnection) the appliance is
operated under the maximum voltage conditions described in Rules 10.1.78 and 10.1.79. current and
voltage readings are taken during the initial five minutes of the test.
10.1.41 Maximum Low Voltage – The maximum voltage used as a basis for the calculation of the
dielectric-withstand potentials specified in Rules 10.1.56 (Direct-Connected Power Supply Dielectric
Withstand Test), shall be determined in accordance with Rules 10.1.42-10.1.45.
10.1.42 To obtain the maximum voltage, any combination of tubes and fuses may be removed.
10.1.43 an automatic voltage-regulating device is rendered inoperative unless, upon investigation, it is
found that it can be relied upon to prevent an increase in voltagethe investigation is to take into
consideration any likely failures in either the regulating device or the appliance, and the possibility of the
device being disconnected, if it isn‟t permanently connected to the circuit.
10.1.44 A connected part or comparable part that is likely to be disconnected during normal operation
or user-servicing, is to be connected during the test, in order that the maximum voltage may be obtained.
10.1.45 If a complex voltage is present, the leak value of voltage is measured.
10.1.46 Electrolytic-Capacitor Test – If the maximum voltage across an electrolytic capacitor is more
than its marked operating=voltage rating, the capacitor shall not short-circuit when subjected to the
following test.
10.1.47 The appliance is operated until the capacitor reaches normal operating temperature after
which all tubes are to be removed except the power rectifier and any other tubes which are necessary to
produce maximum direct-current voltages. The voltage is then measured across the capacitor for 15
minutes. If there is any increase of the leakage current, or a corresponding decrease in voltage, two
additional samples are tested under the same conditions, the electrolytic capacitor is acceptable if all three
samples operate 15 minutes without short-circuited.
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10.1.48 Appliance Dielectric Withstand Test – The insulation and spacing of the appliance shall be
capable of withstanding without breakdown for a period of one minute of the application of the test
potentials described in Rules 10.1.48 and 10.1.56 unless an investigation shows that such breakdown will
not result in a fire or shock hazard.
10.1.49 Primary Circuit Dielectric Withstand Test – A 900 volt 60 Hz potential shall be applied
between any live metal part conductively connected to the supply circuit and any dead metal parts or user
terminals such as antenna and ground leads.
10,1,50 If an isolating power transformer is not a part of the appliance, the test described in Rule
10.1.49 is conducted with the tubes removed, the filament circuits short-circuited and the electrolytic
capacitor and plate-cathode rectifier terminals short-circuited. If the test stresses the insulation of an
adjustable or variable air-dielectric capacitor, the capacitor is short-circuited except that when the
capacitor circuit includes a high resistance to eliminate the shock hazard, the connection to the capacitor
is opened.
10.1.51 Isolating Power Transformer Dielectric Withstand Test – If an isolating type of power
transformer is employed, a 900 volt 60 Hz potential shall be applied between any live or current-carrying
part of the secondary circuit.
10.1.52 Primary Insulation Dielectric Withstand Test – Except in the secondary circuit of an isolating
type of power transformer, a 900-volt 60 Hz potential shall be applied across each capacitor, winding
separation or other insulation required for the elimination of shock hazard, or, which if short-circuited,
would involve a fire hazard either directly or indirectly.
10.1.53 Output Circuit Dielectric Withstand Test – If a speaker is not supplied as an integral part of
the appliance, a direct-current potential of four times the maximum, direct-current, open circuit voltage
measured in the output tube plate circuit shall be applied across a blocking capacitor and between the
primary and secondary windings of an isolating type output transformer whose output circuit is located
from the chassis used for speaker coupling except that the potential shall be not less than 1270 volts.
10.1.54 The test potential may be obtained from any convenient direct-current supply the voltage of
which can be regulated. Starting at zero, the applied potential is increased gradually until the required test
value is reached until breakdown occurs.
10.1.55 Power Transformer Dielectric Withstand Test – A power transformer and the associated
rectifiers socket shall be capable of operating without breakdown when potential is applied to the primary
of the transformer to produce the direct-current test potentials indicated in Rule 10.1.56.
10.1.56 Power Transformer Secondary Dielectric Withstand Test – If a powertransformer is
employed, a direct-current potential of three times the maximum voltage determined in accordance with
the Rules 10.1.42 and 10.1.43 but not less than 500 volts, shall be applied between live parts and
accessible metal parts. A capacitor may be accepted under the provision in Rule 10.1.46. (Electrolytic
Capacitor Test)
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10.1.57 The appliance is connected to any convenient alternating-current supply, , the voltage of
which can be varied and can be brought to a value of not less than three times the rated voltage of the
appliance. The test frequency should not be less than three times the rated frequency of the appliance in
order to permit the rectified secondary voltage to reach the required potential without being limited by the
saturation of the iron of the transformer core.
10.1.58 all lamps and tubes are removed,. And ballast tubes or other automatic regulating devices are
rendered inoperative, if necessary, to carry out the test.
10.1.59 The voice-coil circuit connections and the frame of the loud speakers are connected
electrically to the chassis to ensure that the insulation of the output transformer or capacitor and speaker
field winding is stressed.
10.1.60 Tone controls wave-band switches, and other component parts involving user switching
elements are adjusted to the various operating positions which ensure the connection of these parts in the
circuit under the test.
10.1.61 Electrolytic capacitors are removed from the circuit. Bleeder resistors of other powerconsuming devices are opened at the negative side of the high-voltage filter circuit.
10.1.62 A high voltage rectifier tube with separate filament supply is substituted for the rectifier tube
of the appliance and wired to the rectifier socket. A suitable filter for providing essentially pure direct
current from the external rectifier is connected to the circuit.
10.1.63 A high-resistance voltmeter is connected directly across the rectifier output to measure the
test potential indicated in the Rule 10.1.56 (Power Transformer Secondary Dielectric Withstand Test)
10.1.64 The appliance is connected to the variable source of supply. Starting at zero, the supply
potential is increased gradually until the lowest of the several secondary test voltages is reached or until
breakdown occurs. Upon completion of the test of the lowest-voltage circuit, the circuit is to be
disconnected from the remaining higher-voltage secondary circuits . the same procedure is then followed
in testing the successive higher-voltage secondary circuits, disconnecting each circuit after it has been
tested.
10.1.65 Insulation breakdown will be indicated by an abrupt decrease or retarded advance of the
meter reading.
10.1.66 Direct-connected power supplied dielectric withstand test – if direct connected power supply
is employed, a direct-current potential of three times the maximum voltage determined in accordance with
Rules 10.1.78 and 10.1.79 but not less than 1270 volts shall be applied between live parts of opposite
polarity on the load side of the rectifier.
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10.1.67 The test potential may be obtained from any convenient direct-current supply, the voltage of
which can be varied. Starting at zero, the applied potential is increased gradually until the required test
value is reached until breakdown occurs.
10.1.68 All lamps and tubes are removed and the cathode and plate terminals on the rectifier tube
socket are short-circuited. Electrolytic capacitors are removed from the circuit. Bleeder resistors or other
power-consuming devices are disconnected at the negative side of the circuit.
10.1.69 Printed wiring shock hazard Dielectric Withstand Test – A printed wiring assembly shall
withstand for one minute without breakdown the application of a direct potential of 2E+1000 volts
between printed wiring parts and other parts where electrical breakdown would result in a shock hazard.
10.1.70 Printed Wiring Fire Hazard Dielectric Withstand Test - If the sources of power for a printed
wiring assembly are not limited to 50 watts as described in item A of Rule 10.3.1 the assembly shall
withstand for one minute without breakdown the application of a direct potential of 2E+1000volts
between parts of different potential on the assembly where electrical breakdown involves a path over the
surface of insulating material.
10.1.71 E is the maximum peak potential between the parts when measured with the appliance
operated under the conditions described in Rules 10.1.78 and 10.1.79 or 10.1.42 and 10.1.43 whichever is
applicable.
10.1.72 Accessible Part Dielectric Withstand Test – Except when a conductive shield or coating is
provided between a live part and an accessible metal part or an accessible metal part that is not recognized
as reliable insulation if contact between such parts will result in shock hazard, the direct-current potential
indicated in Table VII shall be applied between these parts.
TABLE VII
DIRECT CURRENT TEST VOLTAGES
Test Potential in Volts
Maximum Peak Potential of Live
Part in Volts (V)*
(DC)
0-1000
Over 1000
3V (1270 Minimum)
2V + 1000
*
Maximum peak voltage between the live part and earth, or an accessible described in Rules 10.1.78
and 10.1.79 or 10.1.42 and 10.1.43 whichever is applicable.
10.1.73 a material that is not recognized as reliable insulation is covered with a conductive coating ,
such as metal foil.
10.1.74 A spark gap or a gaseous-discharge tube may be used as a means of preventing electrical
breakdown in other parts of the circuit if, upon investigation, it is found suitable for the purpose.
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THE PHILIPPINE ELECTRONICS CODE
10.1.75 Power Transformer High-Voltage Secondary – AC Dielectric Withstand Test – Except when
a suitable shield is provided, an alternating potential of four times the rated primary voltage at four times
the rated frequency shall be applicable across the primary voltage at four times the rated frequency shall
be applicable across the primary winding of a power transformer supplying a maximum open-circuit
potential of more than 1000 volts peak between any two terminals of a winding that has no connection to
the chassis. The test potential is applied across the primary winding with one of the winding leads
connected to the chassis. If the secondary winding has no connection to the chassis this test shall be made
with one of the secondary winding and then the other in turn, connected to the chassis.
10.1.76 Power Transformer High Voltage Secondary- DC Dielectric Withstand Test- Except when a
suitable shield is provided, a direct current potential of four times the peak potential measured between
the winding and the chassis shall be applied between the primary winding of a power transformer and any
other winding of the transformer, e.g., a damper tube heater winding, operating at a potential of more than
1000 volts peak, measured under the condition described in Rules 10.1.78 and 10.1.79 with respect to the
chassis if electrical breakdown would result in shock hazard.
10.1.77 Maximum High Voltage VI – The value of VI to be used in calculating the dielectricwithstand test potential specified in Rule 10.1.83 shall be determined in accordance with Rules 10.1.78 ,
10.1.79 and 10.1.82.
10.1.78 All controls are to be adjusted to give the maximum voltage possible with a usable picture.
10.1.79 Voltages are measured with and without any accessories with and without any one tube or
fuse (exclusive of copper or copper alloy links in any low-voltage heater circuit) disabled in any manner
that might occur in service and with any combination of these conditions. In such case, all operating
controls and all user-servicing controls are adjusted to produce the maximum voltage VI, (regardless of
the effect on the picture of a TV set).
10.1.80 Maximum High-Voltage V2 – The value of V2 to be used in calculating the dielectric
withstand test potential specified in Rule 10.1.83 shall be determined in accordance with Rules 10.1.81
and 10.1.82.
10.1.81 Voltages are measured with and without any accessories, with and without combination of
fuses exclusive of copper or copper-alloy links in any low-voltages heater circuit, and tubes removed,
with connectors that are likely to be disconnected during normal operation or user-servicing, both
connected and disconnected, and with any combination of these conditions, in each case, all controls are
adjusted to produce the maximum voltage V2, regardless of the effect on the picture.
10.1.82 In determining the values of V1 and V2 in accordance with Rules 10.1.77 and 10.1.80 an
automatic voltage-regulating device that has been found to be reliable when investigated as described in
Rule 10.1.43 is not rendered inoperative.
10.1.83 High Voltage System Dielectric Withstand Test - A high voltage source over 1000 volts peak
and associated circuits, such as deflection coils, etc., operating in the B-plus circuit, shall be capable of
operating without breakdown for a period of one minute when the high-voltage source output is 1.25V +
1750 Volts or 1.2V2, whichever is greater.
10.1.84 V1 is the maximum voltage measured between any point of the high-voltage source and the
chassis under the conditions described in Rules 10.1.78 and 10.1.79. V2 is the maximum voltage
measured between the same points under the conditions described in Rules 10.1.81 and 10.1.82.
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10.1.85 The voltage applied to the high-voltage source is gradually increased until the required test
value is obtained in the output or until breakdown occurs. The opening frequency and voltage waveform
of the circuit being tested should be maintained as nearly normal as possible.
10.2 Fire hazard Limit
10.2.1 Limited Power Fire Hazard Test – To be free from fire hazards, as described in Rule 9.2.1.J,
the sources of power for a component part or assembly shall not be capable of delivering a power of more
than 15 watts into an externalresistor connected between any two points on the assembly with all
components (including tubes) in place, and
a) If the source of power is directly from the secondary winding of an isolating type transformer, or
motor transformer, the conditions of loading to maximum power and of short circuiting the secondary
winding shall not produce a fire or shock hazard. See item (d).
b) If the source of power employs a resistor to limit the power to 15 watts or less, any conditions of
loading to maximum power or short circuiting the points in question shall not cause the resistor to
change value to the extent that the 15 watt limit to be exceeded.
c) The short or open circuiting (singly) of any rectifier, vacuum tube, transistor, or electrolytic
capacitor between the 15 watt point and the power supply circuit shall not cause the 15-watt limit to be
exceed.
d) Following the tests described in items (a) and (c),. An isolating type of power transformer shall
be capable of withstanding without breakdown for a period of one minute, a 900-volts alternating
potential having a frequency of 60 Hz between (1) any live metal part conductively connected to the
supply circuit and any dead metal parts, and (2) any live or current-carrying part of the primary or
power supply circuit and any live or current-carrying part of the secondary circuit.
10.2.2 To determine if the appliance complies with the requirements in item (a) in Rule 10.2.1, it is to
be tested as described in Rules 10.2.23.A and 10.2.23.B.
10.2.3 For abnormal operation tests, the appliance is connected to a supply circuit fused at 30 amperes
and is placed on a white tissue paper covered softwood surface.
10.2.4 A single layer of cheesecloth is draped loosely over the component under test.
10.2.5 A single layer of Cheesecloth is draped loosely over the whole appliance.
10.2.6 Exposed dead metal parts are grounded through a one-ampere fuse. The supply circuit
connected is to be such that the maximum potential exists between the protective device of the appliance,
if any, and the chassis.
10.2.7 Inherent overheating protection, if provided, is to be investigated to determine the
acceptability.
10,2,8 An abnormal operation test involving stalling a motor or short circuiting or overloading a
component or circuit to maximum power or limited power is conducted until a fire hazard develops. The
circuit under test burns open, or no further change is likely to take place, but not for longer than seven
hours.
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THE PHILIPPINE ELECTRONICS CODE
0.. The term „maximum power‟ is defined as the maximum power that the source of power is
capable of delivering into an external variable resistor connected between the points being investigated.
0..0 The term „limited power‟
is defined as the overload condition that will not cause a
component or protective device to open. To create this condition, sufficient impedance is introduced into
the circuit so that the component or protective device willnot open until a period of six hours has elapsed.
After six hours, the impedance is reduced to cause the component or protective device to open.
10.2.11 A hazardous condition is considered to exist if the test results in any of the following:
a) The single layer of cheesecloth glows or flames
b) The tissue paper glows or flames
c) The one-ampere ground fuse opens
d) Any opening is developed in the overall enclosure (cabinet)A crack that penetrates the
enclosure is considered as an opening.
e) Flame resulting from the arcing continues for more than 15 seconds after arcing is
discontinued.
f) Flame resulting from the test continues for more than 15 seconds unless the material or
component is within an enclosure complying with Rule 9.2.15.P (High Voltage Component
Enclosure). This does not apply to the arcing covered by (e) above.
10.2.12When the circuit is interrupted by the opening of a component or protective device, the test is
repeated twice, using new components when necessary.
10.2.13 When the circuit is interrupted by the opening of a component or protective device, sufficient
impedance is to be introduced (in series with the probe for an arcing test, or increasing the value of the
external load resistor for other abnormal operation test) into the circuit so that the component or device
will not open and the test is to be continued for seven hours except for an arcing test which is to be
continued for a total of 15 minutes at each point. Three complete, separate test are to be made.
10.2.14 A manual-reset type overload protective device is to perform acceptably for 50 cycles of
operation under the most unfavorable of the overload condition.
10.2.15 High-Voltage Arcing Test – With the appliance adjusted as described in Rules 10.1.78 and
10.1.79, a part operating at more than 2500 volts peak and another part of different potential, shall
withstand the following arcing test withoutproducing a fire or shock hazard.
10.2.16 In applying Rule 10.2.15, a part recognized as having a reliable insulation with respect to the
temperature voltage, arc tracking, etc involved need not be subjected to the arcing test.
10.2.17 If an isolation power transformer is employed in the appliance, and arcing involves a part
connected to the supply circuit, test is conducted both with and without one side of the line connected to
the chassis.
10.2.18 The test conditions are described in Rules 10.2.13 and 10.2.17.
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10.1.19 All combustible parts operating at more than 2500 volts peak, and all combustible parts that
form all or part of an enclosure of a part operating at more than 2500 volts peak, are t o be conditioned for
 hours, in a full draft circulating-air oven at a temperature 0 C higher than the normal operating
temperature, but not less than 0 C. the oven is maintain a tolerance of  C. the enclosure mentioned
above refers to the individual enclosure of the high-voltage part and not to the overall enclosure (cabinet)
of the appliance. If during the conditioning mentioned above, wax or other material melt out of parts, the
arcing test is to be conducted on samples in the “as receive “ condition and also on samples that have been
conditioned for 168 hours.
10.2.20 The arc, using the energy available from the parts adjacent is established between the highvoltage part and any adjacent part of different potential where breakdown is likely to occur. The arc is
used to attempt to ignite materials located between the parts of different potential. The arc is established
be means of a conductive probe. The conductive probe may be used to break through insulation (except
recognized wire insulation) or create arc tracking across the surface of insulating materials (e.g., tube
sockets, terminal board, etc.). the arcing is continued for 15 minutes at each location. During the 15
minutes period, the arcing may be stopped at any time by disconnecting the power to the appliance and
the time of flaming measured. If the flame self-extinguishes in less than 15 seconds, the arcing is to be reestablished and continued for a total arcing time of 15 minutes.
10.2.20A Part Disconnection and Component Handling Arcing Test – With the appliance operating as
described in Rule 10.1.78 and 10.1.79, a conductor, a component or lead that may become disconnected
or displaced during shipping or moving of the appliance or that may be disconnected or displaced during
normal operation or user-servicing shall withstand the following arcing test without producing a fire or
shock hazard.
10.2.20B The component lead or connector is brought into contact with any part of different potential
with which contact is likely to be established. If the contact result in arcing, the arc is maintained for 15
minutes. A material that is not recognized is reliable insulation may be considered conductive. A material
located between the lead connector and the part of different potential in the path of possible electrical
breakdown is subjected to the arcing in order to determine if any ignition can be produced. There is to be
no opening of the ground fuse or flaming or glowing of any material for more than 15 seconds following
the discontinuance of the arcing. A condition established only as a result of user servicing of the appliance
and which results in the disabling of all the intended functions of the appliance is permissible.
10.2.20C Noncombustible Part Flame Test – A part is considered non-combustible if it does not
continue to flame for more than 10 seconds after a 15 second application of a test flame, and if it does not
cause the height of the test flame to increase more than one inch during the application of the flame. The
test flame shall be applied five times, the period between the applications being 15 seconds, except that
the test is discontinued if the part continues to flame for more than 10 seconds after any application. The
test flame shall be obtained from 9.5mm diameter. Terrill burner and adjusted to give a flam 12cm high
with 3.75 cm high blue inner cone.
10.2.20D Capacitor Flame Test – A capacitor is considered enclosed in non-combustible material if it
does not continue to flame for more than 15 seconds after the first and second applications of a test flame.
Nor more than 60 seconds after the third test flame, and the period between applications, is 15 seconds.
The test flame is 2 cm. high flames from a 9.5 mm. diameter. Tirrill burner, with the air ports of the
burner closed. The tip of the test flame is to be applied to the body of the capacitor are to be tested.
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10.2.21 Flammability Cl assification or Materials Test  A material or assembly that is to be
classified as self-extinguishing when tested as indicated in Rule 10.2.22 through 10.2.22.C shall:
a) Not have any samples which burn with flaming combustion for more than 30 seconds after each
application of the test flame.
b) Not have a total flaming combustion time exceeding 250 seconds; for the 10 flame applications
for each set of 5 samples.
c) Not have any samples that are entirely consumed before the test of the sample is completed.
10.2.22 For testing a material, the samples are to be flat stock approximately 12.5 cm. long by 12.5
mm. wide and of the smallest thickness, used; or, for an assembly the samples may consist of the
assembly High-voltage transformers, deflection yokes, printed wiring boards, terminal string, etc. may be
tested as finished parts or test samples may be cut from finished parts. In the case of small parts, which
may be consumed before the test is completed, larger samples of the same material may be tested
provided they represent the same or lesser thickness than the part in question. None of the larger samples
is to be entirely consumed.
A. Sets of samples are to be conditioned as follows:
1. Sets of five samples each are to be conditioned for at least 48 hours at a temperature of 23 ±
2°C, and a relative humidity of 50 ± 5 percent prior to testing.
2. Sets of five samples each are to be conditioned in a circulating air oven for a duration of 168
hours at 70 ± 1°C and then cooled in a desiccator, over anhydrous calcium chloride, for at least 4
hours at room temperature prior testing.
B. Samples that consist of an assembly or a section thereof, which are not flat stock samples, will
be positioned in what is considered to be the worst position. Flat stock samples are to be supported with
the longitudinal axis vertical. If the samples meet the requirement, the material of assembly is classified
as self-extinguishing.
C. If more than one sample from a set of five fail to comply with the requirements another set of
five samples may be tested. If all samples from this set comply with the requirements the material is
considered to meet the requirements.
0..3 Unenclosed Component Abnormal Operation Test
 A part that is not provided with an
enclosure in accordance with Rule 9.2.15.D (Component Enclosure), or a part, such as a meter, which is
connected in the circuit for a limited period during the operation of the appliance but which may be
operated continuously under abnormal conditions shall be tested as follows:
To prevent flaming of materials due to arcing between conductors of heater circuits and parts of
higher voltage, the insulation of the conductors should not be unduly damaged by current resulting from
any likely conditions of overloading the heater circuits. Short-circuits that are considered likely to occur
in a series heater string may be stimulated by a connection between (1) any two heater terminals and (2)
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a heater terminal and a terminal of any other element of the tube such that at least one heater or a
portion thereof remains in the test circuit. The heater of any vacuum tube; except a power rectifier tube
with a directly-heated cathode, that obtains its heating power from a low-voltage winding of a power
transformer may be short-circuited.
10.3Abnor mal Operati on
0.3. Power Supply Test  The power supply of an appliance shall be investigated to determine all
of the following:
A. The points nearest the supply circuit no capable of delivering a power of 50 watts or more for
one minute into an external resistor connected singly between each of these points and any return to the
power supply.
B. That a fire or shock hazard is not produced under the condition of separately short-circuiting or
loading to maximum power or limited power, the points determined in (A).
C. That a fire or shock hazard is not produced under the conditions of short-circuiting singly of any
rectifier, vacuum tube, transistor, or electrolytic capacitor in the circuit between the points determined
in item (B) and the supply circuit.
D. The while in a heated condition from the tests, described in items (B) and (C) the power supply
is capable of withstanding without breakdown the dielectric withstand test described in Rules 10.1.4910.1.51
10.3.2 The part and its circuit, with any included vacuum tubes short-circuited, is mounted as
described in the overall enclosure and connected to the power supply circuit.
10.3.3 A motor including one provided with a ship mechanism, is stalled. The secondary of a motor
transformer is connected to its normal load.
10.3.4 The secondary of a motor transformer normally connected across a power supply circuit
without any series vacuum tubes is short-circuited.
0.3.5 Vacuum Tube Filament Short-Circuit Test  There shall be no flame if any material under
any likely conditions of internal short-circuit of a vacuum tube unless the material is within an enclosure
complying with Rule 9.2.15.P (High Voltage Component Enclosure).
10.3.6 A. If the short-circuit tests required by Rule 10.3.1, item (B) above, continue for a full seven
hours, it is not necessary that the maximum power or limited power test be conducted. Likewise, if
the maximum power continues for a fall seven hours, it is not necessary that the limited power test
be conducted.
B. Unless it is necessary to replace component after the tests in item (B) and (C) of Rule
10.3.1 the dielectric withstand test described in item (D) need to conducted only after the last lest
on the power supply is completed.
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C. In conducting the short-circuit tests required by Rule 10.3.1.C. the following connections
are to be simulated:
1) The plate and cathode terminals of a vacuum tube rectifier are to be connected together.
The test is repeated with only the cathode and heater terminals connected together if this
condition is not represented by the first test.
2) The terminals of the rectifier are to be short-circuited, when other than a vacuum tube
rectifier is used.
3) The terminals of an electrolytic capacitor are to be short-circuited.
10.3.7 The test is conducted in accordance with Rule 10.1.2 with all load circuits connected and with
all tubes in place.
10.3.8 A fire hazard is considered to exist if there is emission of flame or molten metal except small
quantities of low-melting temperature alloys such as used in selenium rectifiers, from any component of
the appliance unless the component is within an enclosure complying with Rule 9.2.15.P (High Voltage
Component Enclosure), or is so located that the flaming will not ignite other components of the appliance.
0.3. Picture Tubes Anode Lead Test

Unless marked as in Rule 0.. (High Voltage
Determination Marking), electrical contact between the picture tube anode lead and the chassis earth, or
other parts of the appliance with which contact, either intentional or unintentional by the anode lead is
likely during servicing, shall not (1) cause an electrical breakdown that will produce a permanent shock
hazard, nor (2) subject insulation and spacings, the failure of which would result in a permanent shock
hazard, to a voltage of more than 1270 volts peak during a five minute period, if the arrangement of parts
is such that the voltage is likely to cause an electrical breakdown.
10.3.10 Parts of the appliance with which contact by the anode lead is likely during servicing may
include the antenna terminals, control shafts, deflection-yoke bracket, etc. It is assumed that professional
service personnel may employ jumper leads or disregard mechanical support for the anode lead in order to
effect such contacts.
10.3.11 The appliance is operated under the conditions described in Rules 10.1.78 and 10.1.79. For an
appliance using an isolating power transformer supply, connection is established between the anode lead
and the grounded conductor of the power supply line at the point where the line first enters the chassis
and each side of the power supply line at the point where the line first enters the chassis. The first 15
seconds of the test is conducted with the connection between the anode lead and the connection point
established by means of arcing through air, the distance of the arcing adjusted to produce the maximum
voltage between the accessible metal part and the live part. The remainder of the five-minute period is
conducted with a solid metallic connection established between the anode lead and the connection point.
The measurements are repeated with the attachment-plug cap reversed in the power receptacle.
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0.3. High Voltage Short Circuit Test  An appliance shall not produce a fire or shock hazard
when a high-voltage part in the B-plus circuit, operating at more than 2500 volts peak measured with the
appliance operating under the condition described in Rules 10.1.78 and 10.1.79 is short-circuited to parts
of different potentials, if this represents a single fault.
10.3.13 When an appliance employs a high-voltage oscillator tube, horizontal output tube, damper
tube, or other tube which, because of operating condition or field experience, is considered likely to shortcircuit, the test conditions are to include short-circuits between those elements of the tube that are likely
to short-circuit.
0.3. Cable Arcing Test
 A single or multiple conductor cable as described in Rule ...
(Remote Cable), shall be considered to involve a fire hazard if the arc caused by short-circuiting or
grounding the conductors will ignite surgical cotton.
a) The cable is connected to the appliance and to the remote unit in the intended manner. The
insulation of one of the conductors is removed to expose the bare conductor for a length of
approximately 1.6 mm. A piece of surgical cotton is placed in intimate contact with the bared portion
of the conductor. An ordinary straight brass pin connected to a conductor of opposite polarity, or to
ground return, is touched repeatedly, during a 15-minute period, to the bared conductor in an attempt
to cause arcing.
10.3.15
10.3.16
0.3. Conductive Coating Voltage and Current Test  with a connection between the live part and
any part of the conductive coating mentioned in Rule 10.3.16, including the part where arcing occurred,
the voltage measured by an electrostatic voltmeter between the live part and chassis shall not exceed 1270
volts peak, and the current through a 500 ohm load connected between the live part and chassis shall not
exceed 5 milliamperes.
10.4 Strai n Reli ef and Connectors
0.. Power Supply Cord Strain Relief Test
 The attachment of the power supply cord to the
appliance shall be capable of withstanding a force of 16 kg. applied to the cord as follows: The force is
applied by a 16 kg. weight, or a steady pull of 16 kg. With the chassis in the cabinet in the normal
manner, the force is applied from any angle possible. Three samples are tested. The minimum average
time of holding is 15 seconds. The sample may hold for less than 15 seconds, but not less than five
seconds. The results of the test are not acceptable (1) if the insulation or covering on the flexible cord is
cut or torn, (2) if the bushing slides through the hole in the chassis or enclosure, (3) if cemented on
bushings slide on the cord, or (4) in an interlock connector is separated from the appliance, or is damaged
sot that it does not perform its intended function.
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0.. Tube Plate Lead Strain Relief Stress  The securing means for a horizontal output tube plate
or high-voltage rectifier plate lead located entirely within the high-voltage enclosure shall withstand a
force of 2.3 kg. applied to the lead for one minute on any direction permitted by the construction with the
parts and securing means at room temperature.
0..3 Connector, Cycling Test
 A separable connector shall form acceptably, without damage,
when subjected to the specified number of cycles of make and break at six-second intervals. The test is
conducted with the appliance in normal operation. A connector shall be operated for 10 cycles if it is in a
circuit on the load side of a rectifier and for 50 cycles if it is primary-input circuit.
a) A separable connector is considered one not held in place by a screw, clamp, etc. and which does
not require the use of a tool to accomplish the separation.
10.5 Strength of En closures
10.5.1 Mechanical Loading Test
A. Enclosure Loading Test  The overall enclosure of () a table model appliance weighing more
than 4.5 kg. but not more than 34 kg. or (2) any appliance provided with handles shall withstand for one
minute the loading described below without producing a shock hazard and without any damage that
might result in a fire hazard.
a) The complete appliance is set on a 5 cm. diameter steel ball resting of a horizontal surface
having dimension not less than those of the base appliance. A weight of 0.25W + 1.8 kg. is placed on
top of the appliance directly over the steel ball. W being the weight of the appliance. Rubber-like and
felt materials are removed from supporting feet to the extent that they are likely to be worn off in
normal service. Supporting feet which are not permanent secured to the enclosure are to be removed.
B. Back cover Impact and Bending Test  Except for the back cover of a picture tube enclosure
the back cover of an overall enclosure shall withstand (1) a single-impact of 0.55 kilogram-meters
without the sphere passing through the cover or without producing a shock hazard, and (2) a bending
moment of 0.69 kg. meters without permanent damage to any essential part of the cover, if the cover
has all of the following features:
a) Is of pressed wood or the like.
b) Is used to render parts involving shock hazard inaccessible
c) Has an area of more than 0.135 sq. m.
d) Has a minimum dimension of more than 30.5 cm.
e) For the impact test, the cover is mounted in the intended manner.
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C. Radio Enclosure Impact Test  Parts of a radio enclosure which do not comply with the test
options 4, 5 & 6 of Table III shall withstand a single impact without the developing openings larger
than those permitted by fire and shock hazard requirements or without producing a shock hazard. The
impact shall be 0.69 kg-meter if the enclosure is tested at 90°C, and 0.207 kg. meters if the enclosure is
tested at 60°C or 90°C.
a) During the test, the enclosure is placed against a vertical wall.
D. Radio Enclosure Pressure Test  For an appliance weighing .5 kg. or less, the application of a
force of 6.8 kg. for one minute to any point on the bottom of an overall enclosure, shall not result in a
shock hazard or in damage to any part of the appliance that results a fire hazard.
) Radio Speaker Grills Pressure Test

For an appliance weighing more than .5 kg. the
application of a force of 9 kg. to the speaker grills and the like shall not result in shock hazard or in
damage to any part of the appliance that results in fire hazard.
2) The force specified are applied to the complete appliance by a 1.3 cm. diameter rod and the
end of which is grounded to a 1.3 cm diameter hemisphere.
E. Radio Enclosure Temperature Stability Test  Except as noted in Rule 0.5. G. the enclosure
of live parts shall withstand temperature stability condition described in Rule 10.6.4 without any
shrinkage, warpage, or any other distortion of the enclosure that will (1) interfere with the normal
operation or user servicing of the appliance or (2) result in failure of the appliance to comply with the
requirements in Rule 9.2.15.A (Mechanical Protection) and 9.2.14 D (Accessible Part Shock Hazard)
F. Component Parts such as knobs, windows and inserts that are distorted as a result of the oven
and temperature-stability test may be removed in order to eliminate interference with normal operation
or user servicing of the appliance to comply with the above requirements.
G. At the manufacturer‟s option and as a substitute for the temperature stability test described in
Rule 10.6.4 the complete appliance is placed in a circulating air oven for seven hours. The oven is to be
maintained at a temperature of 90°C; except that the temperature is to be 90°C if the enclosure is of
materials, which has an Izod notched impact strength of not less than 0.2766 kg. meters per 2.5 cm. or
the enclosure withstand a single impact of 0.69 kg. meter. The appliance is not operated during this test.
H. Radio Glass Dial Window that covers a live part, unless of tempered glass 5 mm. minimum
thick, shall withstand a single impact without developing a shock hazard. The impact shall be 0.207 kg.
meters as described in Rule 10.6.2 unless the window is protected by a permanent part of the appliance
that limits the impact form the ball to a lesser value.
I. Television Enclosure Impact Test  The top, sides, and front of an overall television enclosure
used to render live parts inaccessible or to complete the noncombustible enclosure of parts involving
fire hazard, shall withstand a single impact if 0.69 kg. meters as described in Rule 10.6.2 without
developing openings larger than those permitted by fire and shock hazard requirements, or without
producing a shock hazard.
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J. Television Enclosure Pressure Test  The application of a . kg. for one minute to any point of
the bottom of an overall enclosure and a force of 9.1 kg to any other point on the overall enclosure shall
not result in a shock hazard or in damage to any part if the appliance that results in a fire hazard.
a) The forces specified are applied to the complete appliance by a 1.3 cm. diameter rod, the end
of which is rounded to 1.3 cm diameter hemisphere.
K. Television Enclosure Top Loading Test  The application of a force of .kg. for one minute
to any point on the top of the overall enclosure shall not result in a shock hazard or in damage to any
part of the appliance that results in a fire hazard.
a) The 22.72 kg. is applied by means of 5cm. diameter steel ball while the complete appliance is
resting on a horizontal surface.
L. Television Enclosure Temperature Stability Test  The enclosure of live parts shall withstand
temperature stability conditions described in Rules 10.5.1.M or 10.6.4 without any shrinkage, warpage,
or any other distortion of the enclosure that will (1) interfere with normal operation or user servicing of
the appliance, or (2) result in failure of the appliance to comply with the requirements in Rules 9.2.14
and 9.2.15.A.
M. At the manufacturer‟s option and as a substitute for the temperature stability test described in
Rule 10.6.4 the complete appliance is placed in a circulating air oven for seven hours. The oven is
maintained at temperature of 90°C. The appliance is not operated during this test.
N. Television Glass Dial Window Impact Test
 A glass dial window that covers a live part,
unless of tempered glass 5 mm. thick minimum shall withstand a single impact without developing a
shock hazard. The impact shall be 0.69 kg. meters as described in Rule 10.6.2 unless the window is
protected by a permanent part of the appliance that limits the impact from the ball to a lesser value.
O. Picture Tube Enclosure Impact Test  The top, side and front of the enclosure of a picture tube,
including the transparent protective covering over the face of a directly viewed picture tube, shall
withstand a single impact of 0.69 kg. meters as described in Rule 10.6.2 without developing openings
larger than those permitted in Rule 9.2.15.H (Picture Tube Enclosure Openings). The impact, when
applied to the window shall not result in damage to its mounting which will render it unsuitable for reuse, nor shall tempered glass be cracked.
P. Picture Tube Enclosure Back Cover Impact Test  The back cover of the enclosure of a picture
tube shall withstand a single impact of 0.55 kg. meter as described in Rule 10.6.2 without the sphere
passing through the cover, or without producing a shock hazard.
The enclosure is tested with the back cover and picture tube mounted in its normal position.
Q. Picture Tube Enclosure Back Cover Bending Test
 The back cover of the enclosure of a
picture tube shall withstand a bending moment of 0.7 kg. meters as described in Rule 10.6.3 applied for
one minute to any 7.6 length of the perimeter of the cover without permanent damage to any essential
part of the cover.
a) A sheet-steel cover which can be bent and then restored to its original shape without
appreciable loss of mechanical strength need not be subjected to the bending test. However, such a
cover is to have sufficient rigidity to be self-supporting when standing on edge, or is to be provided
with a suitable framework.
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10.6 TEST METHODS
10.6.1 Implosion
A. Two implosion methods are described below. If the implosion can be induced by either method,
the thermal-shock method is to be used unless the high-energy impact method is requested by the
manufacturer. If neither method will induce the implosion, another method is to be used.
1) The thermal-shock method of inducing the implosion is as follows: The rim of the picture tube
adjacent to the seal is to be scratched with a glass cutter, diamond scriber or hard tool. Six 19 mm.
long scratches are made parallel to the center horizontal axis of the tube and spaced to occupy an area
approximately 9.5 mm. in diameter, is heated until nearly fluid. The heated end of the rod is passed
through a prepared access hole in the cabinet and pressed firmly on the scratched surface of the tube.
If implosion does not occur within 10 seconds, the rod is to be withdrawn and cold water is poured
slowly on the scratched area. If implosion is not induced, the process is to be repeated.
2) The high-energy impact method of inducing implosion is as follows. A 2.5 cm. diameter steel
pins is to be inserted through a prepared hole in the cabinet and caused to set on the rim of the tube
near the face seal line. A weight of 4.5 kg. or heavier if necessary to induce an implosion, is made to
fall from a height of approximately 1.4 meters and impact the pin at the end of its free fall. An
equivalent impact may be used. The implosion is restricted so that its travel on impact is only enough
to induce the implosion.
3) To test the enclosure for the picture tube implosion the appliance is to be complete with all
hardware and covers in place except for access holes required for test purposes. A table model
appliance is placed on a 76 cm. high rigid table-like test stand. A floor model appliance tested
standing on the floor. Two barriers, each 1.3 cm. thick, 24 cm. high, and 1.8 meters long, are placed
on the floor. The barriers are located at distances 1 and 1.5 meters from the plane of the front edge of
the enclosure, respectively. A non-skid surface, such as a blanket or rug, is placed on the floor
between the appliance and the second barrier.
B. An appliance complies with the picture tube implosion requirement, if after the induced
implosion of the picture tube, all of the following condition exist:
1) The protective window has not fallen or been expelled from the cabinet as a unit except for
silvers.
2) There is no single piece of glass weighing more than 14.2 grams between the two barriers.
3) The total weight of all pieces of glass between the two barriers is not more than 42.5 grams.
4) There is no glass, except silvers, beyond the barrier that is 1.65 meters from the front end of
the enclosure.
10.6.2 Impact
A. The impact force applied to a part of an enclosure is obtained from a solid, smooth, steel sphere
5 cm. in diameter and weighing 0.5 kg. the sphere is allowed to fall freely from rest through the
distance required to cause it to strike the top of the enclosure with the specified impact. The enclosure is
placed so that the surface tested is vertical and in the same vertical plane as the point of support of the
pendulum. Parts of the enclosure that may interfere with the cord of the pendulum are to be removed.
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10.6.3Bending
A. The bending moment applied to a part of an enclosure such as a production cover, is obtained as
follows: An edge or a corner of the part is to be tested is inserted to make contact with the vertical
edges to the two side pieces of the device. A downward force is applied in a direction perpendicular to
the part, to the opposite edge of the part at a point directly opposite the device. The force is gradually
increased until weight of the device is lifted.
10.6.4 Temperature Stability
A. A sample of the complete appliance applied is placed in a cubical, unvented test cell having a
volume not less than 40 times that of the appliance and so arranged that the circulation of air within the
cell simulates normal room conditions. The air temperature within the cells as measured at the base of
the appliance, is maintained at 60°C. The appliance is connected to a 130-volt supply circuit and
operated continuously for seven hours while resting on a supporting surface having an area
approximately equal to that of the appliance base and centrally located in the test cell.
10.6.5 Test by the Manufacturer
A. Production Line Withstand Test
 Except as noted in Rule 0..5.D each appliance shall
withstand without electrical breakdown, as a routine production-line test, the application of a potential
not less than 350 volts 60 Hz or 500 volts DC, between parts involving shock hazard and accessible
metal parts, for a period of one second.
B. If the factory test potential is greater than that specified in Rule 10.5.5 A, it is recommended, in
order not to cause component degradation, that it must not exceed the manufacturer‟s or vendor‟s
anticipated test potential (component marked rating times a factor for safety) for the individual
component stressed.
C. The test is made when the appliance is complete and ready for packing, or when it is complete
except for parts, such as snap covers or friction-kit knobs, which would interfere with the performance
of the test.
D. The test need not be made on speakers and similar components mounted in cabinets made of
wood or non-conductive material if the components are not likely to be touched or handled in normal
use and if their mounting screws or the equivalent are not exposed on the exterior of the cabinet.
10.7 Marking
0.. Marking Type and Size  A required marking shall be of a permanent and legible type, and
except as noted in Rule 10.7.2 shall be in letter not less than 2.8 mm. high.
10.7.2 The markings of rules 10.7.3 (Identifying and Rating Information), Rules 10.7.5 (Appliance
Installation and Operation Instructions), 10.7.6B (Accessory Installation Instruction), 10.7.7 (Userserviceable Components Directory), 10.7.21 (Parallel-Slot Type Receptacle Marking), 10.7.26
(Protective Devices Replacement Marking), and 10.7.6 (Accessory Identification Marking) need not to
be in 2.8 mm. high letter if distinctive in a smaller type.
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0..3 Identifying and Rating Information  The marking of the appliance shall be readily visible
and shall include the name or trade name of the manufacturer‟s distinctive number of or equivalent
designation, and the electrical rating:
A. The electrical rating of an appliance includes the primary voltage, frequency, (cycles per
second, cycles/second. Hertz, c/s, cps, or Hz), and input in ampere watts.
B. The marking may be located where it is visible only after removing a cover if the cover can be
removed without the use of a tool, and be a combination of chassis markings.
10.7.4 An appliance that incorporates a receptacle that is intended for an external or internal
accessory and that is readily visible without removing covers may be marked to show the appliance and
receptacle ratings separately. If the receptacle for an internal accessory is not readily visible without
removing covers, the electrical rating should include the power input separately, e.g., “Television 0
watts, with remote 00 watts”.
0..5 Appliance Installation and Operation Instructions  An installation diagram or instruction
shall accompany an appliance if the connections and methods of operation are such that there may be any
question regarding them.
0.. Accessory Identification Marking  An accessory for use with an appliance that is not marked
to specify the use of a particular accessory shall be marked to indicate the particular appliance with which
it may be used.
A. The marking may appear either on the accessory or on literature packed with it, or part of the
marking may be on the accessory and part of literature packed with it.
B. Accessory Installation Instructions  Instructions for installing an accessory shall be provided
unless the method of installation or connection of the accessory is obvious. The instruction shall be
located on the receiver, on the accessory, or on literature packed with the accessory.
10.7.7 User-Serviceable Components Directory  The locations and type designation of picture
tubes, and user-serviceable components, e.g., tubes, panel lamps, vibrators, etc., shall be marked on the
appliance where the marking will be readily visible during servicing of the components, unless
replacement of the components by a different type will not produce hazard.
10.7.8 Tube socket branding or a tube directly on the inside of a cabinet or on the underside of a
table type cabinet is considered acceptable.
10.7.9 User-Serviceable Components Servicing Instruction  If user-serviceable parts can be made
accessible by other than the intended method, and if the improper method results in a hazard,
instructions for user-servicing shall be provided to show the intended method; except that instructions
are not required if the intended method is obvious. The instructions, when required, shall be located
where readily visible from the likely approach to using the improper method of user-servicing.
10.7.10 No User-Serviceable Par ts and Compartment Warning  A compartment involving shock
hazard, housing no user-serviceable parts and no plug in type hidden tube or vibrator, shall be marked
where readily visible during any approach to servicing. The marking shall consist of the following
warning or equivalent; “CAUTION-TO PREVENT ELECTRICAL SHOCK. DO NOT REMOVE
COVER (OR BACK). NO USER-SERVICEABLE PARTS INSIDE. REFER SERVICING TO
QUALIFIED SERVICE PERSONNEL.”
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0.. Non-User Serviceable Vacuum Tube Notice  Except as noted in Rule 10.7.11.A there
shall be a notice located adjacent to or part of the marking required in Rule 10.7.10 for a non-userserviceable vacuum tube. The marking shall consist of the following notice or equivalent “VACUUM
TUBE SOLDERED IN PLACE”.
A. The notice need not be provided when:
a) The vacuum tube is not visible through openings in the overall compartment, or
b) It is obvious from the outside of the compartment that the vacuum tube is soldered in place.
0.. Removable Front Cover Warning  If a removable front cover provides protection for live
parts within the picture-tube enclosure in accordance with Rule 9.2.2 Item F.a. a warning notice or the
equivalent shall be visible when the front cover is opened, e.g., “TO PREVENT DANGEROUS
ELECTRICAL SHOCK. REPLACE FRONT COVER BEFORE REPLACING BACK COVER.”
0..3 Picture Tube Window Barrier Warning
 A barrier, such as a mask, that renders parts
involving shock hazard inaccessible when a picture tube is removed or opened during user servicing and
that is secured in place by means that requires the use of a tool for removal of the barrier described in
Item F.b.b in Rule .. shall be marked with a warning against the removal of the barrier, e.g., “TO
PREVENT DANGEROUS ELECTRICAL SHOCK, DO NOT REMOVE THIS MASK.” The marking is
to be located where it will be readily visible after removing or opening the window.
0.. PROJECTION TYPE PICTURE TUBE WARNING  If the replacement of a projectiontype picture tube is not to be considered as a part o f user-servicing, the picture-tube enclosure shall be
marked where readily visible, with a warning against user servicing of the picture tube, e.g.,
“WARNING-HIGH VOLTAGE  DO NOT ENTER.”
0..5 Picture Tube Handling Warning  An appliance employing a picture tube having a
maximum diameter of 15.25 cm. or more shall have a suitable notice located near the tube where it is
readily visible from any approach to removing the tube during any phase of user servicing, including
opening or removing covers. The notice is to be marked with the following warning or the equivalent in
which “FRAGILE GLASS” may be substituted for “HIGH VACUUM”. HIGH VACUUM PICTURE
TUBE IS DANGEROUS TO HANDLE. REFER SERVICING TO QUALIFIED SERVICE
PERSONNEL.
10.7.16 If an appliance contains no user-serviceable parts, the sound sentence of the marking may be
omitted.
0.. Picture Tube Replacement Warning  An appliance employing picture tube having integral
implosion protection shall have a suitable notice located near the tube where it is readily visible from any
approach to removing tube. The warning is to be the following or the equivalent “THE PICTURE TUBE
IN THIS RECEIVER EMPLOYS INTEGRAL IMPLOSION PROTECTION, REPLACE WITH A
TUBE OF THE SAME TYPE NUMBER FOR CONTINUED SAFETY.”
0.. High Voltage Determination Marking  Except as noted in rule 0.., there shall be a
suitable marking describing the proper method of determining the presence of high voltage an the picture
tube anode lead. The marking shall indicate the points to which connections can be made without creating
the conditions described in Rule 10.3.9 (Picture Tube Anode Lead Test). The marking shall be located to
check the high voltage operation.
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10.7.19 The marking need not be provided if the appliance complies with the requirement of Rule
10.3.9 (Picture Tube Anode Lead Test).
0..0 Interlock Warning  An appliance that incorporates an interlock device complying with item
T.b of Rule 9.2.14 (INTERLOCK), shall be marked where it will be readily visible during any approach
to defeat the interlock, with (1) a statement that an interlock is provided to prevent dangerous electrical
shock, with the general location of the interlock, (2) a warning against defeating the interlock, and (3) a
statement that the cover shall be removed for servicing.
0.. Parallel-Slot Type Receptacle Marking  A receptacle of the conventional parallel-slot type
that is utilize for the connection of a part of the appliance shall have the electrical rating in volts,
frequency, and watts indicated by means of a marking on or near the receptacle.
0.. Non-Standard Type Receptacle Marking  A receptacle or connector of other than the
conventional parallel-slot type, with or without a jumpered plug, (1) that in itself involves hazardous
energy, (2) that is readily perceptible by the user, and (3) that is not utilized for the connection of a part of
the appliance, shall be marked, where readily visible, to indicate the specific acceptable accessory or the
acceptable use for which it is intended.
10.7.23 A receptacle or connector is considered readily perceptible by the user if it is recognizable
during the normal procedure of operation or user servicing, visually or by casual touch, or if the presence
of the receptacle is indicated by a marking on the appliance or by literature packed with it.
0.. Fuse Replacement Marking  There shall be a replacement marking adjacent to a fuse or
fuse holder if the fuse is used to prevent fire hazard. The marking shall be located whe re it will be readily
visible during replacement of the fuse and shall consist of the following wording, or the equivalent, e.g.,
“CAUTION  FOR CONTINUED PROTECTION AGAINTS FIRE HAZARD, REPLACE ONLY
WITH THE SAME TYPE 1A-50V FUSE.” If the fuse is soldered in place and is perceptible during user
servicing, the marking shall, in addition to the above, include the following wording or the equivalent,
“REFER REPLACEMENT TO QUALIFIED SERVICE PERSONNEL.” If the available space does not
permit locating the fuse replacement marking adjacent to the fuse or fuseholder, or if the appliance
employs more than one fuse or fuseholder requiring marking, except for the rating, may be at some other
location where it will be readily visible during replace of the fuse.
10..5 Pilot Lamp Replacement Marking  Except as noted in Rule 0.., there shall be a pilot
lamp replacement marking. The marking shall indicate where it will be readily visible during user
servicing and shall consist of the following or the equival ent, “PILOT LAMP SOLDERED IN PLACE.
TO PREVENT ELECTRIC SHOCK, REFER TO QUALIFIED SERVICE PERSONNEL.”
The marking need not be provided when:
a) The pilot lamp is not soldered is placed.
b) The pilot lamp has an estimated life of 5000 hours, or
c) It is obvious during user-servicing that the lamp leads are soldered in place.
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0.. Plug-in Component Replacement Marking  A component such as a resistor of the plug-in
type that is so damage during the tests described in this Code that replacement is necessary, and that is
accessible during user servicing, shall be provided with a distinctive marking identifying the manufacturer
and component type designation; and a marking shall be located on the appliance, where it will be readily
visible during user servicing, indicating the manufacturer, the type designation, and the location of the
component.
0.. It is recommended that records suitable for such use be marked with the words “Slow Burning” or “Safety.”
10.7.29 X-Radiation Under Servicing Conditio n Marking  An appliance that does not comply with
the requirement of Rule 10.1.15 (X-Radiation Under Servicing Condition Test) shall have a suitable
warning located on the chassis where readily visible during servicing. The marking shall consists of t he
following or the equivalent  “SERVICEMAN-WARNING  TO AVOID POSSIBLE EXPOSURE
TO X-RADIATION, TAKE X-RADIATION PROTECTIVE MEASURES (SEE SERVICE MANUAL)
FOR PERSONNEL DURING SERVICING.
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XI. RADIATION HAZARDS
11.1 GENERAL
11.1.1 OBJECTIVE
11.1.2 EXAMPLES OF ELECTRONIC PRODUCTS SUBJECT TO
RADIATION CONTROL
11.2 PERFORMANCE STANDARDS FOR ELECTRONIC PRODUCT
11.2.1 RESPONSIBILITY
11.2.2 PERFORMANCE STANDARD FOR TELEVISION RECIEVERS
11.2.3 PERFORMANCE STANDARD FOR COLD CATHODE
DISCHARGE TUBES
GAS
11.2.4 PERFORMANCE STANDARS FOR MICROWAVE OVENS
11.3 SAFETY REQUIREMENTS IN THE UTILIZATION OF RADIATION
EMITTING EQUIPMENT
11.3.1 BASIC STANDARD ON RADIATION PROTECTION FROM XRAY DIAGNOSTIC AND ASSOCIATED EQUIPMENT
11.3.2 RADIATION HAZARDS ASSOCIATED WITH TRANSMITTERS
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SECTION XI
RADIATION HAZARDS
11.1 GENERAL
Radiation, covered in this Code, means any sonic, infrasonic or ultrasonic wave which is emitted
from an electronic product as a result of the operation of an electronic circuit in such product. The
protective measures in this Code are for preventing adverse effects of any ionizing or non-ionizing
electromagnetic radiation. Electromagnetic radiation includes the entire electromagnetic spectrum of
radiation of any wavelength. The electromagnetic spectrum includes, but is not limited to, gamma rays,
X-rays , ultraviolet, visible, infrared, microwave ,radio wave and low frequency radiation.
11.1.1 OBJECTIVE
Radiation, although beneficial in the development of man, poses hazards of varying degrees which
can be harmful to the electronic product manufacturers, users and the general public. Hence, proper
control of the manufacture and use of radiation emitting devices in necessary.
11.1.2 EXAMPLES OF ELECTRONIC PRODUCTS SUBJECT TO RADIATION CONTROL
The following listed electronic products are intended to serve as illustrative examples of sources of
electronic production radiations to which the regulations of this section apply.
A. examples of electronic products which may emit X-rays and other ionizing electromagnetic
radiation, electrons, neutrons and other particulate radiation include:
Ionizing electromagnetic radiation:
Television receivers
Accelerator
X-ray machines ( industrial, medical, research, educational)
Particulate radiation and ionizing electromagnetic radiation
Electron microscope
Neutron generators
B. Examples of electronic products which may emit ultraviolet, visible, infrared, microwaves, radio
and low frequency electromagnetic radiation include:
Ultraviolet:
Biochemical and medical analyzers
Tanning and therapeutic lamps
Sanitizing and sterilizing device
Black light sources
Welding equipment
Visible:
White light devices
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Infrared:
Alarm systems
Diathermy units
Dyers, ovens and heaters
Microwave:
Alarm systems
Diathermy units
Dryers, ovens and heaters
Medico-biological heaters
Microwave power generating devices
Radar devices
Remote control devices
Signal generators
Radio and low frequency:
Cauterizers
Diathermy units
Power generation and transmission equipment
Signal generators
Electromedical equipment
C. Examples of electronic products which may emit coherent electromagnetic radiation produced
by stimulated emission include:
Laser:
Art-form, experimental and educational devices
Biomedical analyzers
Cauterizing, burning and welding devices
Cutting and drilling devices
Communications transmitters
Range finding devices
Maser:
Communications transmitters
D. Examples of electronic products which may emit infrasonic, sonic and ultrasonic vibrations
resulting from operation of an electronic circuit include:
Infrasonic:
Vibrators
Sonic:
Electronic Oscillators
Sound amplification equipment
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Ultrasonic:
Cauterizers
Cell and tissue Disintegrators
Cleaners
Diagnostic and nondestructive testing equipment
Ranging and detecting equipment
11.2. PERFORMANCE STANDARDS FOR ELECTRONIC PRODUCTS
The standards listed in this section are prescribed pursuant to section 2 of Presidential Decree No. 480
dated June 6, 1974and are applicable to electronic radiation from such products. Standards so prescribed
are subject to amendment or revocation and additional standards may be prescribed as are determined
necessary for the protection of the public health and safety.
11.2.1 RESPONSIBILITY
Every manufacturing and local supplier of an electronic product to which an applicable standard is an
effect under this Section shall be responsible for the compliance of their product to the Safety Standards
set herein.
11.2.2 SAFETY STANDARDS FOR TELEVISION RECIEVER
A. Exposure rate limit. Radiation exposure rates produced by a television receiver shall not exceed.
0.5 milliroentgens per hour at a distance of five (5) centimeters from any point on the external surface
of the receiver, as measured in accordance with this section.
B. Measurements. Compliance with the exposure rate limit shall be determined by measurements
made with instruments, the radiation sensitive volume of which shall have a cross section parallel to the
external surface of the receiver with an area of ten (10) square centimeters with no linear dimension
larger than five (5) centimeters.
Measurement s made with instruments having other areas must be corrected for spatial nonuniformity of the radiation field to obtain the exposure rate average over a ten (10) square centimeter
area.
All measurements shall be made with the receiver displaying a usable picture and with the power
source operated at supply voltages up to the maximum test voltage of the receiver and with all user
controls and all service controls adjusted to combinations which result in the production of maximum
X-radiation emissions.
C. Critical component warning. The equipment shall have permanently affixed or inscribed
warning labels, clearly legible under conditions of service, on all television receivers which could
produce radiation exposure rates in excess of the requirements of this section, as a result of failure or
improper adjustment or improper replacement of a circuit or shield component. The warning label shall
include the specification of operating high voltage and an instruction for adjusting the high voltage to
specified value.
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11.2.3 SAFETY STANDARDS FOR COLD CATHODE GAS DISCHARGE TUBES.
A. Exposure Rate Limit. Radiation exposure rates produced by cold cathode gas discharge tubes
shall not exceed 10 microentgens per hour at a distance of thirty (30) centimeters from any point on the
external surface of the tube, as measured in accordance with this section.
The divergence of the exit beam from tubes designed primarily to demonstrate the effects of Xradiation, with the beam-blocking device in the open position, shall not exceed π (Pi) steradians.
B. Measurements. Compliance with the exposure rate limit of cold cathode gas discharge tubes
shall be determined by measurements averaged over an area of one hundred (100) square centimeters
with no linear dimension greater than twenty (20) centimeters.
Measurements of exposure rate from tubes in closure from which the tube cannot be removed
without destroying the function of the tube, may be made at a distance of thirty (30) centimeters from
any point on the external surface of the enclosure, provided:
(1) In the case of enclosures containing tubes designed primarily to demonstrate the production of
X-radiation, measurements shall be made with any beam-blocking device in the beam-blocking
position; or
(2) In the case of enclosure containing tubes designed primarily to demonstrate the effects of a flow
of electrons, measurements shall be made with all movable or removable parts of such enclosure in
the position which would maximize external exposure levels. Measurements shall be made under
the conditions of use specified in instructions provided by the manufacturer.
Measurements shall be made with the tube operated under forward and reverse polarity.
C. Instruction, Labels and Warnings. Manufacturers and local suppliers shall provide or cause to be
provided, with each tube to which this section is applicable, appropriate safety instructions together
with instructions for the use of such tube, including the specification of a power source for use with the
tube.
Each enclosure or tube shall have inscribed on or permanently affixed to it, tags or labels, which
identify the intended polarity of the terminals and:
(1) In the case of tubes designed primarily to demonstrate the heat effect, fluorescence effect, or
magnetic effect, a warning that application of power in excess of that specified may result in the
production of X-rays in excess of allowable limits: and
(2) In the case of tubes designed primarily to demonstrate the production of X-radiation, a warning
that this device produces X-rays when energized.
The tag or label required shall be located on the tube or enclosure so as to be readily visible and
legible when the product is fully assembled for use.
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11.2.4 SAFETY STANDARDS FOR MICROWAVE OVENS
A. Power Density Limit. The power density of the microwave radiation emitted by a microwave
oven shall not exceed one (1) milliwatt per square centimeter at any point 5 centimeters or more from
the external surface of the oven, measured prior to acquisition by a purchaser, and therefore, 5
milliwatts per square centimeter at any point 5 centimeter or more from the external surface of the oven.
B. Measurements and Test Conditions. Compliance with the power density limit in this section
shall be determined by measurements of microwave power density made with an instrument system
which (1) reaches 90 percent of its steady state reading within 3 seconds when the system is subjected
to a stepped input signal and (2) has a radiation detector with an effective aperture having no
dimension exceeding 10 centimeters. This aperture shall be determined at the fundamental frequency of
the oven being tested for compliance. The instrument system shall be capable of measuring the power
density limits of this section with an accuracy of plus 25 percent and minus 20 percent (plus or minus 1
decibel).
Microwave ovens shall be in compliance with the power density limit if the maximum reading
obtained at the location of the greatest microwave leakage does npot exceed the limit specified in
subparagraph 11.2.4 A when the leakage is measured through at least one stirrer cycle.
Measurement shall be made with the microwave oven operating at its maximum output and
containing a load of 275 = 15 milliliters of tap water initially at 20 degrees = degrees centigrade placed
within the cavity at the center of the load-carrying surface provided by the manufacturer. The water
container shall be a low form 600 milliliter beaker having an inside diameter of approximately 8.5
centimeters and made of an electrically nonconductive material.
Measurements shall be made with the door fully closed as well as with the door fixed in any other
position which allows the oven to operate.
C. Door and Safety Controls. (1) microwave ovens shall have a minimum of two operative safety
interlocks one of which must be concealed. A concealed safety interlock on a fully assembled
microwave oven must not be operable by (a) any part of the body, or (b) a rod 3 millimeters or greater
in diameter and with a useful length of 10 centimeters. A magnetically operated interlock is considered
to be concealed if a test magnet, held in place on the oven by gravity or its own attraction, cannot
operate the safety interlock. The test magnet shall have at zero air gap of at least 4.5 kilograms and a
pull at 1 centimeter air gap of at least 450 grams when the face of the magnet which is toward the
interlock switch when the magnet is in the test position is pulling against one of the large faces of a
mild steel armature having dimensions of 80 millimeters by 50 millimeters by 8 millimeters.
(2) Failure of any single mechanical or electrical component of the microwave oven shall not cause all
safety interlocks shall be inoperative.
(3) Service adjustments or service procedures on the microwave oven shall not cause the safety
interlocks to become inoperative or the microwave radiation leakage to exceed the power density limits
of this section as a result of such service adjustments or procedures.
(4) Insertion of an object into the oven cavity through any opening while the door is closed shall not
cause microwave radiation leakage from the to exceed the applicable power density limits specified in
this section.
D. Instructions. Manufacturers and local suppliers of microwave ovens to which this section is
applicable shall provide or cause to be provided:
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(1) To servicing dealers and distributors and to others upon request, each oven model, adequate
instructions for service adjustments and service procedures including clear warnings of
precautions to be taken to avoid possible exposure to microwave radiation.
(2) With each oven, adequate instructions for its safe use including clear warnings of precautions
to be taken to avoid possible exposure to microwave radiation.
11.3 SAFETY REQUIREMENTS IN THE UTILIZATION OF RADIATION EMITTING
EQUIPMENT
11.3.1 BASIC STANDARDS ON RADIATION PROTECTION FROM X-RAY DIAGNOSTIC
AND ASSOCIATED EQUIPMENT
The best available standards on Radiation Protection from X-ray equipment are those laid by the
Radiation Health Office Department of Health. The Radiation Health Office was created under
Presidential Decree No. 480, dated June 6,1974 and it has been entrusted with the responsibility of issuing
rules and regulations for the purpose of adequate radiation protection and effective control of radiation
hazards. The Radiation Health Office, since then, has been in active coordination with the International
Commission on Radiological Protection and on November 14,1975, the RHO has issued standards
applicable to diagnostic equipment installed after November 4, 1975.
These Basic Standards on Radiation Protection laid down by the Radiation Health Office are
therefore adopted and made part of the Philippine E lectronics Code (See Annex “A” of this section).
11.3.2 RADIATION HAZARDS ASSOCIATED WITH TRANSMITTERS
A. Radio transmitters emit radio frequency electromagnetic radiations which can be harmful to
operators who have to be near such equipment for prolonged periods of time. Exposure of the operators
to electromagnetic radiation does not become a serious problem until irreversible effects take place.
Such effects can be included by the radio frequency radiations. Exposure to intense r-f radiation
produces a purely thermal effect; but this can cause the eye to develop opacities of the lenses
(cataracts), and can be irreversible. Sometimes the cells will recover, but the damaged cells can become
self-regenerating. Damage to cells of reproductive tissues is called genetic, and damage to other cells is
called somatic. The somatic damage has been known to become malignant (cancer or leukemia) or, in
milder form,. It may appear as an apparent acceleration of the aging process.
The amount of r-f radiation varies as the frequency varies, the higher the frequency the higher the
density of r-f radiation. Hence, the highest densities for a given power level will occur in narrow
microwave beams. It must not be assumed, however, that there are no danger at the lower frequencies.
Radio-frequency energy may penetrate as much as one-tenth wavelength at microwaves, but at longer
wavelengths the penetration may be much less than 1/1,000 of a wavelength.
The amount of power absorbed by the body also varies with frequency and consequently the
tolerable power density varies.
In one set of experiments, an eye cataract was developed in an animal after 90 minutes of exposure
at a power 290 milliwatts per square centimeter. The safe level of exposure is obviously much less than
this.
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B. Permissible damage rate. Genetic and somatic effects are accumulative, but most other effects of
X-radiation are not accumulative. The accumulative effects place an upper limit on the total radiation
dose, and this is measured in roentgens per hour. (abbreviated mr per hr). the total dose is then
determined by multiplying the rate by the number of hours of exposure.
The maximum radiation from electronic equipment must not exceed 100 mr per week. The
radiation may not be absorbed in the tissue at the site of interest, and another unit called the rad
(radiation absorbed by dose) refers to the amount of radiation actually absorbed. Rads and roentgens are
roughly equivalent in quantity. A rep (roentgen equivalent physical) refers to radiation other than Xrays which will cause an absorption equal to 1 roentgen. Different sources of radiation have different
effects which are related to X-rays by a number which is referred to as the rbe (relative biological
effectiveness). The rbe dose is expressed in rems(roentgen equivalent man) or rebs (roentgen equivalent
biological).
Rems = rbe x rads
Alpha particles are and fast neutrons have an rbe of 10, but any radation produced by a radio
transmitter will have an rbe of 1.
The maximum accumulated permissible dose (MPD) to the whole body is calculated thus:
MPD = 5 (N-18)
Where MPD = rems
N= person‟s age
This was specified by the National Committee on Radiation Protection and Measurement (U. S. A)
C. Recommended Safe Particles
(1) There may be danger areas in the vicinity of the transmitter. If an operator suspects an arc or a
flash inside a transmission line, waveguide or power amplifier cavity, he should never attempt to
make a small opening to look inside with the power on. All joints should be closed as tightly as
possible.
() A section of “waveguide beyond cutoff” are sometimes used for aircooling purposes in the
output cavities of high powered amplifiers; and although r-f radiation should be negligible
through these tubes, there is nothing to stop X-rays, and an operator should not hold his eye close
to one of these openings.
It should be noted that a person wearing eyeglasses is not protected by such eyeglasses.
Eyeglasses can actually focus r-f radiation into the eye.
(3) Even with relatively low-powered transmitters, dangerous power densities are present over the
cross-section of the wave guide. An operator should never look into an energized waveguide.
(4) Radiation shields provided by manufacturers of radiation emitting electronic products, must
not be removed, or substituted or its purpose defeated by the operator when the equipment is in
operation.
(5) Warning labels or inscriptions provided by manufacturers on radiation emitting electronic
products must not be removed, erased, altered or obliterated.
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A N N E X “A”
Republic of the Philippines
Department of Health
OFFICE OF THE SECRETARY
Manila
March 4, 1976
MEMORANDUM:
TO
SUBJECT
: All concerned
: Implementation of the Basic Standards on Radiation Protection laid down by the
Radiation Health Office, Department of Health Manila pursuant to Presidential
Decree No. 480, dated June 6, 1974.
For the information and guidance of all concerned, attached herewith is a copy of the Basic Standards on
Radiation Protection, with reference to Section 1 (d) of Presidential Decree No. 480 dated June 6, 1974.
To ensure safety of radiation workers, users and the general public from the hazards caused by ionizing
and non-ionizing radiation, the full support and cooperation of your respective office must be extended
for the effective achievement of the President‟s desire to improve the radiation protection practice in the
Philippines.
Strict compliance with the attached Basic Standards on Radiation Protection is strongly enjoined.
Please be guided accordingly.
(SGD.) CLEMENTE S. GATMAITAN, M.D. M.P.H.
Secretary of Health
IMPORTANT
: The Regional Health Directoris requested to disseminate copies of this
Memorandum to all personnel concerned under his region. Please comply
BASIC STANDARDS ON RADIATION PROTECTION
LAID DOWN BY THE RADIATION HEALTH OFFICE (RHO)
AFTER APPROVAL BY THE SECRETARY OF HEALTH
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RHO follows in its activities the basic recommendations on Radiation Protection made by the
International Commission on Radiological Protection (ICRP). As stated in the Presidential Decree No.
480, RHO has been entrusted with the responsibility of issuing rules and regulations for the purpose of
adequate radiation protection and effective control of radiation hazards. The following standards effective
November 14, 1975 are limited to X-ray diagnosis and shall with regard to the technical requirements
apply to all X-ray diagnostic equipment installed after November 14, 1975.
RHO is aware of the fact that the present X-ray diagnostic installations do not entirely conform with
these standards. It is important to recognize that efficiency and safety in the utilization of radiation
equipment is influenced not only by the design of the equipment but also by the manner of its use. RHO
will encourage the use of modern equipment but recognizes the existence of circumstances where
unconditional disapproval of existing equipments may result in unjustified deprivation of valuable
medical attention. However, RHO will, when practicable prescribe in a given permit the extent and
purposes to which an existing facility may be used, without large-scale renovations.
1. X- r ay diagnostic an d associated equi pment
1.1 General
1.1.1 Every X-ray tube used for diagnostic purposes shall be enclosed in a housing such that the
exposure from the leakage radiation measured at a distance of one meter from the focus does not exceed
100 mR in one hour at every rating, specified by the manufacturer for that tube in that housing.
1.1.2 Diaphragms, cones or collimators shall be used to limit the useful beam to the area of clinical
interest and shall be so constructed that in combination with the tube housing, they comply with the
exposure requirements stated in paragraph 1.1.1.
1.1.3 In assessing compliance with the requirements in paragraphs 1.1.1 and 1.1.2 is adequate for
measurements to be averaged over and area up to but not larger than 100cm 2 at a focus distance of one
meter.
1.1.4 The minimum permanent total filtration in the useful radiation beam shall be determined by the
maximum voltage specified for the tube in the housing. The permanent total filtration for normal
diagnostic work shall be equivalent to not less than:
2 mm A1 at voltage up to and including 100kV
3mm A1 above 100kV
The total filtration permanently in the useful beam shall be indicated on the tube housing.
Exception: In special procedures at operating potentials below 50 kV (e.g. mammography) the
minimum total permanent filtration shall be equivalent to at least 0.5 mm A1. Where special equipment is
not employed means shall be provided which ensure that the tube is not used at higher potentials with
inadequate protection.
1.1.5 When more than one tube can be operated from a single control panel there shall be clear
indication on the control panel as to which the tube is connected.
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1.2
Flouroscopy
1.2.1An adjustable collimator or diaphragm shall be provided to define the useful beam.
1.2.2 The X-ray tube, collimating device and fluoroscopic screen or image intensifier shall be linked
together in such a way that under normal operating conditions, the beam will not fall outside the screen
irrespective of the source-screen distance.
1.2.3 The fluorescent screen shall be covered with a protective glass sheet having a lead equivalent of
not less than:
2.0 mm for apparatuses having a maximum operating potential up to and including 70 kV
2.0 mm for apparatuses having a maximum operating potential up to and including 100 kV an
additional 0.01 mm per kV above 100 kV
Image intensifier and adjacent mounting parts subject to the useful beam exposure shall provide the
same protection as the required for the conventional screen assembly.
1.2.4 If the equipment permits spot films to be taken in connection with the fluoroscopic examination,
the protective power of the fluorescent screen and/or of the devices mentioned in paragraph 1.2.3 shall be
determined for the maximum radiographic potential if it exceeds the maximum potential of fluoroscopy.
1.2.5 In fluoroscopy the focus skin distance must not be less than 30 cm and should not be less than
45 cm except for the chest where the focus skin distance must not be less than 45 cm and should not be
less than 60 cm.
1.2.6 Means (control settings or meters) shall be provided to indicate the X-ray tube potential and
current also when image intensifiers with automatic control are used.
1.2.7 A device shall be provided by which the fluoroscopist is informed about the fluoroscopic time
used.
1.2.8All tables and stands for fluoroscopy shall be provided with adequate means for protecting the
fluoroscopist and his assistants against scattered radiation. A shield equivalent to not less than 0.5 mm
lead shall be provided to cover openings such as the bucky slot. The fluoroscopist shall be protected b a
drape which may consist of overlapping parts to facilitate palpitation. The lead equivalent of the drape
shall not be less than 0.5mm. it shall be attached to the lower edge of the screen holder when the latter is
vertical and to the edge nearest the fluoroscopist when the screen is horizontal. When the image
intensifiers are used, the same degree of protection shall be provided as is required for conventional
fluoroscopy.
1.3. Radi ography
1.3.1 Means shall be provided to check that the film is aligned with the beam.
1.3.2 The minimum distances between the focus and the patient in radiography shall be the same as
stated in paragraph 1.2.5. this paragraph is not applicable for dental radiography.
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1.3.3 Means (control settings or meters) shall be provided on the control panel to indicate the X-ray
tube potential and current and the exposure time or to indicate whether timing is automatic. A meter to
indicate the product of milliamperes and time(mAs meter) may be used in place of current and/or
exposure time indicator.
1.4. Oth er techn ical protective device
1.4.1 Protective aprons and gloves shall have a lead equivalent of at least 0.25 mm.
1.4.2 Mobile X-ray equipment shall be so designed that the minimum distance of the operator from
the tube and patient during the mobile radiographic procedures is at least 2.
1.5 Responsibilities
1.5.1 Those who manufactured or trade in X-ray equipment, and any person hiring out such
equipment for use, shall ensure that the equipment when it is delivered for use, or is displayed for sale or
advertising purpose in the Philippines, is provided with protective devices conforming with these
standards and also otherwise offers satisfactory protection against harmful effects of radiation, and also
that detailed instructions are provided for the installation and operation of the equipment.
1.5.2 If X-ray equipment is installed by an independent person, he must ensure that all protective
devices prescribed are mounted and that the other instructions for the installation are complied with.
2. Str uctur al shi eldi ng for X -r ay diagnosis
Radiation work in new or modified installation shall not commence until RHO has given its
permission. Plans for these installations should, with regard to the structural shielding, preferably be
reviewed in advance by RHO.
3. Wor ki ng pr ocedur es
3.1 Radiation Workers
3.1.1 It is the duty of any person involved in radiological work to take all practicable precautions to
avoid being unnecessarily irritated, taking into account the nature of the work, the circumstances under
which it is performed, the working experience of those employed in it, and other relevant conditions,
paying particular attention to what is prescribed in these standards or otherwise by RHO.
3.1.2 It is the duty of all persons engaged in radiological work to use devices prescribed for radiation
protection, to follow carefully the directives given by RHO, and otherwise to exercise appropriate care
and, in so far as their duties require, to assist in preventing injuries caused by radiation.
3.1.3 No person shall operate X-ray equipment without adequate technical competence nor apply
radiological procedures without adequate knowledge of the physical properties and the harmful effects of
ionizing radiation.
Radiation has the responsibility to state the various level of knowledge necessary for different
categories of ancillary personnel engaged in X-ray diagnostic work.
3.1.4 No person shall remain in an X-ray room when radiological procedures are being carried out,
unless his presence is essential.
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3.1.5 Whenever possible, members of the staff shall remain behind protective screens or shield during
all types of examinations. If that cannot be done during fluoroscopic examinations or when the patient has
to be assisted during exposure, protective aprons shall be worn and when practicable also protective
gloves.
3.1.6When patients must be held during examinations, all efforts shall be undertaken to avoid having
this assistance provided by persons who work within the X-ray department. No pregnant woman or
persons under the age of 18 years shall be permitted to hold patients. Persons holding the patients shall
wear protective aprons and gloves. Even if protective clothing is worn, those holding the patients shall
make sure as far as practicable, that no part of their body, even if covered by protective clothing is in the
path of the beam.
3.2 Patients
3.2.1 Protective measures in the widest sense also include good clinical judgment and good,
operational practice as well as competent interpretation of diagnostic information. Good clinical judgment
implies that no patient should be exposed unnecessarily as far as can be judged when the exposure is
decided. Once a technique of radiological examination has been chosen, it shall be applied with a
minimum patient exposure, consistent with securing the desired diagnostic information.
3.2.2 The basic protective requirement is that the radiation dose to the patient, especially the integral
dose and the dose to the gonads and the active bone marrow, shall not be greater than necessary to obtain
the relevant diagnostic information.
3.2.3 Medical exposure of humans shall never occur as a result of administrative decisions, e.g. for
legal purposes, without due consideration of the relevant medical data and the need for the examination of
each individual case.
3.2.4 Special precautions shall be taken with regard to the protection patients awaiting examination.
Waiting rooms with adequate protection shall be available and any exposure which is not part of the
diagnostic procedure shall be subject to the limitations that apply to non-medical exposure.
3.2.5 All diagnostic x-ray work shall be performed with the most appropriate combinations of
operating potential, filtration, focal-skin distance, field limitation and sensitivity of the recording system.
It is of primary importance to decide on the minimum field size of the region of interest. The field size
may be smaller than but in no case larger than the size of the film or screen to be used.
3.2.6 Special precautions shall be taken in order to make retakes of radiographs unnecessary.
3.2.7 Good processing techniques are essential for protection of the patient. The correct developer and
fixer shall be selected for the type of film to be used. The darkroom shall be adequately lightproof and the
operations in the darkroom shall be undertaken under conditions of extreme cleanliness.
3.2.8 Before a direct fluoroscopic examination is begun the eyes shall be sufficiently dark-adapted.
To enable work to be carried out with the lowest possible exposure rate the adaptation time shall be at
least 15 minutes.
3.2.9 The exposure rate for the direct fluoroscopy, as measured at the patient entrance surface, shall
be as low as practicable and should not exceed 5R/min.
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