ELECTRICAL DESIGN LECTURES:
THE SERVICE ENTRANCE CONDUCTORS
Pow
Power is suppl
supplie
ied
d to a build
building
ing thro
throug
ugh
h a servi
service
ce entra
entrance
nce.. Three
Three heav
heavy
y wires,
ires, toge
togeth
ther
er call
called
ed the
the drop
drop,, exte
extend
nd from
from a
utilit
utility
y po
pole
le or an under
undergr
grou
ound
nd sourc
source
e to the
the struct
structure
ure.. These
These wire
wires
s are
are twist
twisted
ed into
into a cabl
cable.
e. At the
the build
buildin
ing,
g, over
overhe
head
ad wire
wires
s
are
are faste
fastene
ned
d to the
the struct
structure
ure and
and spli
splice
ced
d to servi
service
ce entra
entrance
nce wire
wires
s that
that ente
enterr a cond
condui
uitt thro
throug
ugh
h a servi
service
ce head
head,, as shown
shown
in Figure 31-1
In plan
plannin
ning
g over
overhe
head
ad servi
service
ce drop
drop pa
path
ths,
s, minim
minimum
um heig
height
ht requ
require
ireme
ment
nts
s for
for conne
connecto
ctorr lines
lines must be care
careful
fully
ly follo
followe
wed.
d.
See
See Figure
Figure 31-2.
31-2. If thes
these
e dista
distance
nces
s canno
cannott be ma
maint
intai
aine
ned,
d, rigid
rigid cond
conduit
uit,, elec
electri
trica
call me
meta
talli
llic
c tubin
tubing,
g, or busw
busway
ays
s (chan
(channe
nels,
ls,
ducts) must be used.
If the
the serv
servic
ice
e is supp
suppli
lied
ed unde
underg
rgro
roun
und,
d, thre
three
e wires
ires are
are place
laced
d in a rigi
rigid
d cond
condui
uit.
t. An unde
underg
rgro
roun
und
d serv
servic
ice
e cond
condui
uitt is
brou
brough
ghtt to the
the me
mete
terr socke
socket.
t. An under
undergr
grou
ound
nd servi
service
ce entra
entrance
nce inclu
include
des
s a wattatt-ho
hour
ur me
mete
ter,
r, ma
main
in brea
breake
ker,
r, and
and light
lightnin
ning
g
prot
protec
ecti
tion
on.. Autom
Automat
atic
ic brow
browno
nout
ut equip
equipme
ment
nt is also
also requ
requir
ired
ed by ma
many
ny code
codes
s for
for new
new const
construc
ructi
tion
on.. All
All elec
electri
trica
call syste
systems
ms
must be grounded through the service entrance.
SIZE AND RATINGS
2
Serv
Servic
ice
e drop
rop shal
shalll have
have suffi
suffici
cie
ent ampaci
pacity
ty to carr
carry
y the
the load
load.. They
They shal
shalll not
not be smal
smalle
lerr than
than 8mm
8mm (3.2mm
2
diameter) copper or 14 mm aluminum or copper clad aluminum
Service entrance conductors shall be sufficient size to carry the computed loads.
CLEARANCE
CLEARANCE OVER THE ROOF (CONDUCTORS OF NOT MORE THAN 600 VOLTS):
1. 2500 mm (8 feet) - without elevation
2. 1000 mm (3 feet) - without elevation
CLEARANCE
CLEARANCE FROM GROUND (CONDUCTORS OF NOT OVER 600 VOLTS)
1. 3100 mm - above finished grade, sidewalks
sidewalks or from any platforms or projection which may be reached.
2. 3700 mm - over residential driveways and commercial areas such as parking lots and drive-in
establishments not subject to truck traffic.
3. 4600 mm - over commercial areas, parking lots or agricultural or other areas subject to truck traffic.
4. 5500 mm - over public streets, alleys roads and driveways on other than residential property.
Note : (drawing is based on NEC standard)
s tandard)
UNGROUNDED CONDUCTORS SHALL NOT BE SMALLER THAN:
1.100A, 3- wire, for one family dwelling with six or more 2 branch circuit.
2.100A, 3-wire, for
f or one family dwelling with an initial computed load of 10-kw or above.
3. 60A for other loads.
EXCEPTIONS:
2
2
1. For loads consisting of not more than two wire branch circuit, 8 mm (3.2 mm dia.) copper or 14 mm
aluminum or copper clad aluminum.
2
2
2. By special permission, for loads limited by demand or by the source of supply, 8mm copper or 14mm
aluminum or copper-clad
c opper-clad aluminum.
2
2
3. For limited loads of a single branch circuit 3.5mm copper or 3.3mm aluminum or copper-clad
c opper-clad aluminum.
INSTALLATION
INSTALLATION OF SERVICE CONDUCTORS:
Service entrance conductors shall be installed in accordance
acc ordance with the applicable requirements
requirements of this code
(PEC) covering the type of wiring method used and limited to the f ollowing methods:
methods:
1. Open wiring on insulators
2. Rigid metal conduit (RMC)
3. Intermediate Metal Conduit (IMC)
4. Electrical Metallic Tubing (EMT)
5. Service-entrance cables
6. Wireways
7. Busways
8. Auxiliary Gutters
9. Rigid non-metallic conduit
10. Cable Bus
11. Type MC cable
12. Mineral-insulated
Mi neral-insulated metal-sheathed
metal-sheathed cable
PROTECTION:
Servi
Service
ce entra
entrance
nce cond
conduct
uctor
ors
s shall
shall be insta
install
lled
ed in acco
accord
rdan
ance
ce with
with the appl
applica
icabl
ble
e requ
requir
irem
emen
ents
ts an
and
d subje
subjecte
cted
d to ph
physi
ysica
call da
dama
mage
ge shall
shall be prot
protec
ecte
ted
d in
any of the following ways or methods:
methods:
1. By RMC
2. By IMC
3. By Rigid Nonmetallic Conduit suitable for the locations
4. By EMT
5. Type
Ty pe MC Cable
C able or other approved means
means
THE SERVICE EQUIPMENT-DISCONNECTING MEANS
GENERAL:
The Servi
Service
ce Equip
Equipme
ment
nt-Di
-Disco
sconne
nnecti
cting
ng Me
Mean
ans
s shall
shall be prov
provid
ided
ed to disco
disconne
nnect
ct all
all cond
conduct
uctor
ors
s in a bu
build
ildin
ing
g or ot
othe
herr struct
structure
ure from
from th
the
e servi
service
ce en
entr
tran
ance
ce
conductors.
IMPORTANT PARTS OF AN ELECTRICAL DES IGN
1. Service Drop
Service Drop
Service Entrance
Service Head / Cap
Conduit
Service Meter
Service equipment
OVERHEAD SERVICE
Not to Scale
Private Pole
Service Drop
Building
Service
Entrance
Conduit
Service Meter
Service equipment
UNDERGROUND SERVICE
Not to Scale
Service Drop Clearance Over Roof (Without Elevation)
2500 mm
BUILDING
Street
HOUSE
Side
Walk
To Service Equipment
Service Drop Clearance Over Roof (With Elevation)
1000 mm
BUILDING
Street
HOUSE
Side
Walk
To Service Equipment
3700mm
3700mm Clearance from Ground. Over residential driveways and other drive-in establishment
establishment not subject to traffic
To nearest pole
3700mm
To Service Entrance
Sidewalk
Car port
Road
5500mm
5500mm Clearance from Ground. Over public streets, alleys, roads and driveways an other residential properties.
BUILDING
5500mm
Side
Walk
Side
Walk
Roadway
To Service Equipment
3100mm Clearance from ground. Above finished grade, sidewalks and from any platform or projection which might be reached.
BUILDING
3100mm
Roadway
Side
Walk
Finished Gr ade
Line
To Service Equipment
Lighting Design Lecture
Functional lighting design must consider the interaction among eyesight,
objects, and light sources. Good lighting design provides sufficient but not
excessive light. Glare from unshielded bulbs or improperly placed lighting
should be avoided. Excessive contrast between light and shadows within
the same room should also be avoided, especially in work areas.
For centuries, candles and oil lamps were the major source of artificial
light. Although candles continue to function for special effects, the major
sources of light today are incandescent and fluorescent lamps.
Incandescent lamps have a filament (a very thin wire) that gives off light
when heated. Fluorescent lamps have an inner coating that gives off visible
light when exposed to ultraviolet light. The ultraviolet light is released by a
gas inside the fluorescent tube. Incandescent lamps concentrate the light
source, while fluorescent lamps provide linear patterns of light. Fluorescent
lamps give a uniform glare less light that is ideal for large working areas.
Fluorescent lamps give more light per watt, last seven times longer, and
generate less heat than incandescent lamps.
Light Measurements
Human eyes adapt to varying intensities of light. However, they must be given enough time to adjust slowly to different light levels. Sudden extreme
changes of light may cause discomfort. Light intensity is measured in units called foot candles. A foot candle is equal to the amount of light a candle
casts on an object one foot away. See Figure. 31-8. Ten foot candles (10 fc) equals the amount of light that ten candles throw on a surface one foot
away. In the metric system, the standard unit of illumination is the lux (lx). One lux is equal to 0.093 fc. To convert foot candles to lux, multiply by 10.764.
See Fig. 31-9.
Types of Lighting
The three basic types of lighting are general lighting, specific lighting, and decorative lighting.
SPECIFIC LIGHTING: Light
directed to a specific area or
located to support a particular
task is known as specific,
local, or task lighting. See
Fig. 31-11. Specific lighting
helps in performing such
tasks as reading, sewing,
shaving, computer work, and
home theater viewing. it also
adds to the general lighting
level. Track lighting and
portable
lamps
provide
sources of specif ic indoor
lighting.
GENERAL LIGHTING: General lighting
provides overall illumination and radiates a
comfortable level of brightness for an entire
room. See Fig. 31-10. General lighting
replaces sunlight and is provided primarily
with chandeliers, ceiling or wall-mounted
fixtures, and track lights. To avoid contrast
and glare, general lighting should be diffused
through the use of fixtures that totally hide the
light source or that spread light through
panels. Close spacing of hanging fixtures also
creates diffuse lighting. Another solution is to
use adjustable fixtures so that the light can be
directed away from eye contact. W here
possible, daylight should be included as a part
of the general lighting plan during daylight
hours. If adequate window light is not
available, the use of skylights should be
considered. The intensity of general lighting
should between 5 and 10
fc (54 to 108lx). A higher level of general lighting should be used in the service area and bathrooms. Many general lighting
fixtures can also be used for decorative lighting by a connection to dimmer switches.
DECORATIVE LIGHTING: Bright lights are
stimulating, while low levels of light are
quieting. Decorative lighting is used to create
atmosphere and interest. Indoor decorative
lights are often directed on plants,
bookshelves,
pictures,
wall
textures,
fireplaces, or any architectural feature worthy
of emphasis. Some decorative lighting can be
used as general lighting through the use of
dimmer switches. Outdoor decorative lighting
can be most dramatic. Exterior structural and
landscape features can be accented by wellplaced lights. Outdoor lighting is used to light
and accent wall textures, trees, shrubs,
architectural features, pools, fountains, and
sculptures. See Fig. 31-12. Outdoor lighting is
especially needed to provide a safe view of
stairs, walks, and driveways. Remember to
conceal light sources and don't over light. use waterproof devices and an automatic timing device to turn lights on and off.
Light Distribution
Light from any artificial source can be distributed (dispersed or directed) in five different
ways: direct, indirect, semi=direct, semi-indirect, and diffused. See Fig. 31-13. Direct light
shines directly on an object from a light source. Indirect light is reflected from surfaces.
Semi direct light shines mainly down as direct light, but a small portion of it is directed
upward as indirect light. Semi-indirect light is mostly reflected, but some light shines directly.
Diffused light is spread evenly in all directions with the light source (bulb) not visible.
Reflection
All objects absorb and reflect light. Some white surfaces reflect 94 percent of the light that
strikes them. Some black surfaces reflect only 2 percent. The remainder of the light is
absorbed. All surfaces in a room act as a secondary source of light
when light is reflected. Refer again to Fig. 31-10. Excessive reflection causes glare. Glare can be eliminated from this secondary source by using matte (dull) finish surfaces and by avoiding exposed light bulbs. Eliminating
excessive glare is essential in designing adequate lighting.
Structural Light Fixtures
Light fixtures are either portable plug-in lamps or structural fixtures. Structural fixtures are wired and built into a
building hard-wired. These must therefore be shown on electrical plans and specifications. Structured fixtures may be
located on ceilings, on interior and exterior walls, and on the grounds around the building. Different light patterns are
produced, depending upon the type of light fixture. Figure 31-14 illustrates the types of structural light fixtures
described in the following paragraphs.
1.00 Soffit lighting is used to direct more light to wall surfaces and to horizontal surfaces, such as kitchen
and bath countertops, wall desks, music centers, and computer centers.
2.00
Cove lighting directs light (usually fluorescent) onto ceiling surfaces and indirectly reflects light into the
center of a room. The soffit should hide the fixture from view from any position in the room.
3.00 Valance lighting directs light upward to the ceiling and down over the wall or window treatment. Valance
faceboards can be flat, scalloped, notched, perforated, papered, upholstered, painted, or trimmed with
molding.
4.00 Cornice lighting directs all light downward. It is similar to soffit lighting. except cornice lights are totally
exposed at the bottom.
Wall Fixtures
Wall fixtures are used as a source of general lighting, as well as decorative lighting when attached to a dimmer switch.
Wall spotlights or fluorescent fixtures may also be used as task lighting. Wall spotlights for accents, diffusing fixtures
for general lighting, and sconces are used extensively on walls. See Fig. 31-15. Vanity lights and fluorescent tube
lights are also used on walls as task lighting.
DESIGN COMPUTATION
Design Analysis where necessary shall be included on the drawing or may be submitted on separate sheets of uniform size paper, shall show:
1. Illumination design computations and tabulated lighting levels in lux for critical areas in institutional, industrial, recreational and commercial buildings.
Provide lighting fixture schedule.
Example:
General Description and
Application
Symbol (1)
Item Number
(2)
General
Description (3)
Specification
Description
Lamp and Power Data
Manufacturer
Typical
Application
(4)
Type (5)
Quantity x w/
lamp (6)
Lamp Holder
(7)
Supply Volts
(8)
Watts per fix and Catalog
Number Series
(9)
Notes (11)
(10)
1. Legend used
2. Item Number
3. Standard description. Example:
Surface-mounted two lamp-40 watts, 230 VAC Industrial-type fluorescent lighting fixture with diffuser with spring loaded lamp holder and
high pf energy saving ballast.
4. Where fixture will be mostly likely to be used
5. Ballast type: Electronic or Electromagnetic
6. Lighting Fixture Quantity
7. Type of lamp holder: Twistlock type or Spring type.
8. Voltage requirement
9. Number of lamp times lamp wattage
10. Supplier description and catalog number (if available)
11. Other particular items (dimensions and Gauge size).
For Gauge Size use the f ollowing table for reference
Table 1: Gauge Size
Imperial
Gauge
10.00
12.00
14.00
16.00
18.00
20.00
22.00
24.00
26.00
Imperial in
mm
3.25
2.64
2.03
1.63
1.22
0.91
0.71
0.56
0.46
Metric sheet
mm
3.00
2.50
2.00
1.50
1.20
0.90
0.70
0.60
0.50
2. Feed lines and protective devices of motors, electrical equipments and appliances indicating types and ratings.
3. Size of branch circuit wires, feeders, sub-feeders and busbars including protective devices.
4. Size and type of service entrance wires, raceways and equipment.
In designing building load. It is essential to consider the simultaneity factor (demand factor) to determine the energy consumption of the building. Use the following table:
A p p ro x im ate Valu es fo r s im u ltan eity fac to rs to c o n s u m er s
Office
Building
0.80-0.90
0.20-0.40
0.70-0.90
0.80-1.0
0.80-1.0
0.60-0.75
0.50-0.70
System
Lighting
Outlets
HVAC
Heating
Refrigeration
Kitchens
Elevators
Hoisting Equipment
Others
Total
0.30-0.40
0.70-0.80
Dem an d Valu es fo r ro u g h es tim atin g
Load
Industr ial
Hospitals
Residentials
Type of Structure
0.95
0.10
0.80-1.0
0.80-1.0
0.90-1.0
0.60-0.75
0.30-0.90
0.80-0.90
0.35-0.45
0.30-0.70
0.70-0.90
0.10-0.20
0.70-0.90
0.10-0.25
0.80-1.0
0.90-1.0
0.60-0.60
0.80-1.0
0.80-1.0
0.90-1.0
0.60-0.80
0.60-0.70
0.60-0.85
0.60-0.80
0.30-0.60
0.30-0.60
Office Buildings
Hospitals
Laboratories (including
cages)
Housing
Retail (department stores,
etc)
Computer Labs
Commercial Kitchen
(in
2
W/m
50 - 100
120 - 50
100 - 350
Note:
* in W per unit
** in W per Diner
4-6*
50 - 60
400 - 800
400 - 700**
Depth below site surface for buried conn ections (according to DIN 18012 Europ ean Standard)
Land Surface
35 - 60 cm
note (for encoding):
minimum spacing for meter center (fig 8.18,pg 342)
minimum spacing for mvsg (fig 8.19,pg 343)
proper installation requirement for indoor oil immerse type xformer (fig 8.22,pg 345)
minimum spacing for xformer (fig 8.3,pg 346)
50 - 100 cm
communications supply
gas supply
60 - 100 cm
60 - 80 cm
high voltage supply
district heat supply
120 - 150 cm
water supply
5. Settings / ratings of overcurrent devices.
For items 2 to 5 consider the following:
a. The maximum allowable voltage drop per wire.
Table 2: Maximum Allowable voltage drops (percent)
Portion of Distribution
System
For Lighting
and Power
Load
For
Electrical
Heating
For Power
Only
1
1
2
1
1
3
3
1
3
5
3
8
Service Entrance to
panelboard
Feeder to distribution center
Branch circuit to connected
load
Overall maximum voltage
drop
b. Size and installation of wire
b.1 See Single Family Dwelling computation below for proper wire sizing. Use the following guidelines:
o
b.1.1 The allowable ampacity of conductors is reduced at ambient temperatures higher than 88 F (NEC Wire Ampacity Table 2), and also when more than 3 conductors are installed in the raceway.
Sample:
o
Two Sets of 120/208-volt, 3Ø, four wire distribution system feeders are installed in a common conduit that passes through a boiler room with a maximum ambient temperature of 102 F. The demand
o
current of Feeder 1 is calculated to be 100A, and that for Feeder 2 is 50A. Determine the feeder sizes based on 90 C copper wires (cables), and select the common conduit size. Assume selected
feeders are type THHN copper.
Answer:
There are four wires in each set of feeders, or eight for Feeders 1 and 2. Theoretically, the neutral conductor may not carry any current if the load is balanced between Phases A, B, and C. However,
recent design practices have to treat the neutral conductor as a current-carrying conductor, due to the third harmonics of inductive loads such as PC and electronic appliances. From NEC Table 3, a
correcting (derating) factor of 0.7 must be applied.
o
o
The ambient temperature in the boiler room is 102 F; thus, a correction (derating) factor of 0.91 nuts be applied for the 90 C rated wires (cable) (see NEC Table 2).
The overall derating factor for ampacity is 0.70 x 0.91 = 0.637; thus, Feeder 1 must be selected for 100A / 0.637 = 157A, and Feeder 2 must be selected for 50A / 0.637 = 78.5A.
From NEC Table 1, Feeder 1 must be a minimum size of 1/0 AWG, which is rated for 170A under normal condition, and Feeder 2 must be a minimum size of No. 4 AWG.
From NEC Table 5 No. 1/0 THHN cable has 0.1893 sq.in. of cross-sectional area, and that for No. 4 cable is 0.0845 sq.in. The total cross-sectional area of all the cables is: [{(4) x 0.1893} + {(4) x
0.0845}] = 1.160 sq.in. Based on the maximum 40% fill rule, the conduit must have a minimum cross-sectional area of 1.160 / 40 percent or 2.9 sq.in. From NEC Table 4 a 1 1/2 inch conduit has a
cross-sectional area of 2.04 sq.in. Thus, the next larger size 2-inch conduit having a cross-sectional area of 3.36 sq.in must be used.
b.1.2 The installation of wires (or cables) in raceway is strictly regulated. Generally, no more than 40% of the cross sectional area of the raceway can be filled with wires or cables. The limitation is necessary
for 2 reasons:
I. To prevent excessive heat build-up.
even a fire.
All wires have resistances and impedances that creates loss that turns into heat and, if unabated, may cause the breakdown of the insulation material or
II. To permit the physical installation of wires.
damage.
Wires in conduits must be pulled into the conduits by special tools. A clear space must be provided for the wires to be pulled in easily, without
b.1.3 When the raceway (conduit) is too long or contains too many bends, pull box must be installed at the location to facilitate the pulling of conductors into the raceway.
I. For Angle or U Pull Box:
For boxes where the conductors are pulled at an angle or in a "U" condition, the distance between each conduit entry inside the box, and the opposite wall of the box should not be less than six
times the trade diameter of the largest conduit , and the distance must be increased for additional conduit entries by the amount of the sum of the diameter of all other conduit entries on the
same wall of the box . the distance between the conduit entries should not be less than six times the trade diameter of the largest raceway .
L1
25mm
L2
40mm
25m
40mm
Sample:
The 40mm diameter conduit is the largest therefore:
L1 = 6 x 40mm + (25mm + 25mm) = 290 mm (minimum)
L2 = 6 x 40mm + (25mm) = 265mm (minimum)
D = 6 x 40mm = 240mm (minimum) where D = distance between raceway entries enclosing
the same conductor
II. For Straight Pull:
In straight pulls, the length of the box should not be less than eight times the trade diameter of the largest conduit . The depth of the box should be sufficient enough to permit installation of the
largest lock nut and bushing of the conduit including the spacing between the adjacent conduit entries.
25mm dia
H
40mm
Sample:
The 40mm diameter conduit is the largest therefore:
L = 40mm x 8 = 320mm
H = whatever height necessary to provide proper installation of the conduit locknuts and
bushing within the enclosure.
L
b.1.4 When the conductors need to be spliced, a junction box is required. No conductor is allowed to have splice within a raceway other than at the junction boxes or within equipment enclosures.
b.2 with respect to voltage drop
Use the f ollowing computation in determining the voltage drop
CM = (25 x I x L) / Vdrop
(based on NEC computation)
where: CM = circular mil
I = Full Load current (100%)
L = Length (in feet)
V drop = Voltage Drop (see table 2 for reference)
Sample:
Panelboard LP A @ 100% load: 117.76
Amperes
Distance from Panelboard to EE room: 80
meters
CM = (25 x I x L) / Vdrop
where : I = 117.76 A
L = 80m(100cm / m)(1 in / 2.54cm)(I ft / 12in)
= 262.47feet
V drop (set at 5%) = 240 x 0.05 = 12.0v
CM = (25 x 117.76 x 262.47) / 12.0
=
64,392.64 CM
2
A = d finding d
d = sq.rt (64392.64)
= 253.76
= 253.76 CM (1in / 1000mils)(25.4mm/in)
= 6.445 mm
A = 3.1416 x (6.445)2 / 4
2
2
safe
A = 32.63 mm or 38 mm
therefore Use 1 set of 3 #38mm2 and 1 #22mm2 THHN in 40Ø IMC
NUMBER OF DISCONNECTING MEANS:
The service disconnecting means for each set or for each sub-set of service entrance conductors shall consist of not more than six switches or six circuit
breaker mounted in a single enclosure, in a group of separate enclosures, or on a switchboard.
LOCATION:
The service disconnecting means shall be installed either inside or outside of a building or other structure at a readily accessible location nearest to the
point of entrance of the service entrance conductor.
RATING:
The service disconnecting means shall have a rating not less than the load to be carried.
IN NO CASE SHALL THE RATING BE LOWER THAN SPECIFIED THROUGH:
a. ONE CIRCUIT INSTALLATION - The service disconnecting means shall have a rating of not less than 15 amperes.
b. TWO CIRCUIT INSTALLATION - The service disconnecting means shall have a rating of not less than 30 amperes.
c. ONE FAMILY DWELLING - The service disconnecting means shall have a rating of not less than 100 amperes, 3 wire under either of the following
conditions:
1. Where the initial computed loads is 10 KW or more:
2. Where the initial installations consist of six or more 2 wire branch circuit.
d. ALL OTHERS - for all other installations the service disconnecting means shall have a rating of not less than 60 amperes.
Note:
- The service disconnecting means shall simultaneously disconnect all ungrounded conductors and shall be capable of being closed on a fault to or
greater than the maximum available short-circuit current.
- The service entrance conductors shall have a short-circuit protective device in each underground conductors.
- Fuses shall have an interrupting rating not less than the maximum available short circuit current in the circuit at their supply terminals.
- Circuit Breakers shall be free to open in case the circuit is closed in the overload. Circuit Breakers shall have an interrupting rating no less than the
maximum available short-circuit at its terminals.
ELECTRICAL WIRING DESIGN OF A SINGLE FAMILY DWELLING
Principles:
1. Secure the architectural plan of the building to be lighted.
2. Determine the loads and systems to be provided like air-conditioning units , electric range, washing machine and other appliances.
3. Determine the location and concentration of loads and specify the location of electrical devices, appliances and controls in the architectural plan.,
4. Determine the number of branch circuits conductors to be provided. Compute their corresponding sizes basing from the known electrical loads.
5. Determine the number and rating of feeders for lightning and power.
6. Determine the rating and sizes of the service equipment and service entrance.
7. Draw the wiring diagram. Make the location plan. Write the specification and draw the symbols and legends used.
8. Estimate the cost of the project.
LOADS AND SYSTEMS TO BE PROVIDED IN A SINGLE FAMILY DWELLING:
Branch circuits and feeder calculations (Article 3.3 of P.E.C)
1. General Lightning Load:
Read rule 3.3.1.2 (b)
Use table 3.3.1.2 (b)
2. Small Appliances:
Read rule 3.3.1.3 (b)
And rule 3.1.2.7 (b)
3. Cooking Range:
Read rule 3.1.2.1 (b)
And rule 3.3.2.10
Use Table 3.3.2.10
4. Clothes Dryer:
Read rule 3.3.2.9
Use table 3.3.2.9
5. Laundry Loads:
Read rule 3.3.2.7 (b)
Read rule 3.3.1.3 ©
6. Water Pump (motor):
Read article 6.6
Use table 6.6.12.2
Tables 6.6.12.3
Tables 6.6.12.4
7. Air Conditioning Units:
Read article 6.7
Section 6.6.2
8. Permissible loads:
Read rule 3.1.2.5
9. Fixed Appliances:
Read rule 3.3.2.8
10. Standard sizes of overcurrent protections:
Read rule 4.5.1.5
11. Feeder Neutral Load:
Read rule 3.3.2.13
12. Sizes and ampacity of conductor
Use table 5.3.2.4
13. Sizes of Conduit:
Use table 12.1.1.3 (a to c)
page 52
page 53
page 55 and rule 3.3.2.7 (a) page 57
page 48
page 45
page 58
page 59
page 57
page 58 for demand factor
page 57
page 55
pages 335-370; section 6.6.2 page 344
page 366 for single phase motors
page 367
For two and three motor
page 366
page 371-380
same as motors
page 47
page 57
page 151
page 58
page 182
page 678 to 680
SINGLE FAMILY DWELLING DESIGN
Design a single family dwelling with the following electrical loads:
small appliance load = 3000 watts
1 - 12 kw electric range
1 - 2.5 kw water heater
2 - 1Hp ACU
1 - 1/2 Hp ACU
Note:
The area of the dwelling unit is 150 square meters
1 - 5kw washing machine
Using conventional method (Area method), design the electrical system.
Computations:
2
2
For General Lighting load (150m ) x (24 W/m )
For small appliance load
compute load without electric range
Application of Demand Factors
First 3000 at 100% demand factor
Excess of 3000VA (6600-3000) at 35%
Other Loads:
Electric Range
washing Machine
Two 1 Hp air conditioning unit (2 x 8 x 230)
water Heater
One 1/2 Hp ACU (4.9 x 230)
25% of largest motor (0.25 x 8 x 230)
Total Computed load with electric range
=
=
3,600.00
3,000.00
6,600.00
=
=
3,000.00
1,260.00
4,260.00
=
=
=
=
=
=
8,000.00
5,000.00
3,680.00
2,500.00
1,127.00
460.00
25,027.00
Main Feeder full load current:
IL = 25027 / 230 = 108.81 amperes
For Main Feeder service entrance conductor:
2
Use 2 - 38mm THW copper conductor (minimum)
Use 125A , 250V, 2 pole Circuit Breaker, 300AF
For Service neutral conductor:
IN = 70% (108.81) = 78.17 amperes
2
Use 1 - 22mm THW copper conductor
Size of Conduit:
Use 32mm phase rigid steel conduit (RSC)
Load Schedule
Circuit No.
L.O.
1
10
2
3
4
5
6
7
8
9
10
10
C.O
8
8
Load Description
Switch
Power
Voltage
Current
Amp trip
Amp Frame
Circuit No.
Conductor
10 - 40 w Fluorescent Lamp
10
400w
230v
1.74
15
30
1
2.0 mm
8 - 40 watts
8 - 180 watts
8 - 180 watts
1 - 12kw Electric Range
1 - 5kw Washing Machine
1 Hp - ACU
1 Hp - ACU
1 Hp - ACU
One 1/2Hp ACU
10
320w
1440w
1440w
12000w
5000w
230v
230v
230v
230v
230v
230v
230v
230v
230v
1.39
6.26
6.26
52.17
21.74
8.00
8.00
8.00
4.90
15
15
20
20
60
30
20
20
20
30
30
30
100
60
30
30
30
30
2
3
4
5
6
7
8
9
10
2.0 mm
2
3.5 mm
2
3.5 mm
2
14 mm
2
5.5 mm
2
3.5 mm
2
3.5 mm
2
3.5 mm
2
3.5. mm
Design the electrical system of a single family with one hundred sq meters (100 sq. m) and with the following connected loads:
2 small appliances at 1500 w each
One 15 kw electric range
One 4.5 kw electric range
One 1.2kw washing machine
One 5kw clothes dryer
Two 1.5Hp ACU
One 3/4 Hp ACU
Compute for the size of the feeder and the main circuit breaker
Computations:
General Lightning Load
(100sqm (24w / sqm)
Small Appliance Load = 2(1500)
total computed load without fixed appliances
Application of Demand factor:
First 3000 w at 100% demand factor
excess at 35% demand factor
total computed load without fixed appliances
Other load:
One 15kw Electric range = 8 + 8(15-12)5%
One 4.5kw oven = 4.5(80%)
One 1.2kw washing machine
One 5kw clothes dryer
total computed load without ACU
computed current, I = 22840 / 230
Two 1 1/2 Hp ACU = 2(10)
One 3/4 Hp ACU
Plus 25% of the full load current of highest motor
total load current
Maximum Ampacity of subfeeder circuit:
I = 125% (128.7) + 25%(10)
Therefore:
=
=
2,400.00
3,000.00
5,400.00
=
=
3,000.00
840.00
3,840.00
=
=
=
=
9,200.00
3,600.00
1,200.00
5,000.00
22,840.00
99.30
20.0 A
6.90 A
2.50
101.80
=
=
163.38 A
=
=
=
=
3,000.00
6,440.00
2,550.00
3,500.00
15,490.00
=
=
67.22 A
84.00 A
2
Use: 2 - 60mm THW
Note: 125% is for safety allowance
Subfeeder neutral conductor (line to line voltage 230):
small appliance load
electric range = 9200 (70%)
oven = 3600 (70%)
clothes dryer = 5000 (70%)
total load
Neutral current
I = 15490 w / 230 v
I = 67.22 (125%)
2
Use:
2 - 60mm THW copper conductor
2
1 - 30mm THW co er conductor
conduit size: 1 - 40mm dia Rigid Steel Conductor (RMC)
Size of Circuit Breaker : Use 175A / 200AF, 250, 2 pole
Wiring Design Computation for Feeder (6-dwelleing units)
2
2
General Lighting = 6 (100m ) (24 w/m )
Small Appliance load = 6 (2)(1500)
Computed Load for gen lighting & small appliance
Application of demand factor:
First 3000w at 100% demand factor
Excess at 35% demand factor
Net computed load
Other Loads
6 - 15kw E.R = 21 + (15-12)(5%)(21)
6 - 4.5 kw oven = 6(4.5)(0.43)
6 - 5 kw clothes dryer = 6(5)(70%)
6 - 1.2 kw washing machine
Computed load without A.C.U
Current I = 77250 w / 230v
6 - 1.5 Hp ACU = 2(6)(10)
6 - 3/4 Hp ACU = 6(6.9)
plus 25% of full load current of highest motor of the 6 units
= (lo)(25%)
feeder load current
minimum ampacity of circuit conductor
I = 125% (499.17) + 25%(10)
number of conductor size available
= 626.46 / 2
=
=
=
14,400.00
18,000.00
32,400.00
=
=
3,000.00
10,290.00
13,290.00
=
=
=
=
=
24,150.00
11,610.00
21,000.00
7,200.00
77,250.00
=
=
=
335.87
120.00
1.40
=
2.50
499.17
=
626.46
=
313.23
=
18,000.00
=
=
3,000.00
5,250.00
=
=
=
=
16,905.00
8,127.00
14,700.00
47,982.00
208.60
=
=
=
200.00
6.02
206.02
2
use 4 - 200mm THW (2 conductors in parallel)
minimum ampacity of feeder neutral conductor
IN = 313.23(70%) = 219.26A
Another computation for feeder neutral:
small appliance load = 6(2)(1500)
application of demand factor
first 3000 w at 100% demand factor
excess at 35% demand factor 35%(18000-3000)
other loads:
electric range = 24150 (70%)
oven = 11610 (70%)
clothes dryer = 21000 (70%)
total neutral current
feeder neutral current = 47982 / 230
application of demand factor:
200A at 100% demand factor
excess at 70% demand factor = 8.6(70%)
feeder neutral current
for safety allowance
IN = 125%(206.02) = 257.52
128.70 A
Poles
Conduit
2
2
15mm phase RSC
2
2
2
2
2
2
2
2
2
2
15mm phase RSC
15mm phase RSC
15mm phase RSC
20mm phase RSC
15mm phase RSC
15mm phase RSC
15mm phase RSC
15mm phase RSC
15mm phase RSC
Therefore:
2
use : 4 - 200mm THW copper conductor
2
1 - 125mm THW copper conductor
conduit : use 2 - 80mm dia RSC
Maximum ampacity of feeder circuit overcurrent protective device:
use 600AT / 1000AF, 250V circuit breaker
Note : Washing machine may be included in small appliance load, however, washing machine is not included in other loads to reduce size of conductor.
DESIGN OF COMMERCIAL BUILDING
Less than 400 sq. ft - Provide at least 1 convenience outlet for every 20 ft (6 meters).
First 400 sq. ft or 37 sq. m----------------------------------------------4 convenience outlet
Additional 400 sq. ft------------------------------------------------------2 convenience outlet
Fraction--------------------------------------------------------------------2 convenience outlet
LOAD SCHEDULES
Panel Board LPA
Ckt. No.
Circuit Breaker Rating
Load Description
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
F
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
T
15
15
15
15
15
15
15
15
15
15
15
15
15
15
15
P
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
100w
10
8
8
8
8
8
5
9
16
50
15
2
10
17
50
15
2
Spare
18
19
20
21
50
50
50
50
15
15
15
15
2
2
2
2
Spare
Spare
Spare
Space
40w
4
Switches
S1
4
1
3
S2
1
1
1
1
1
1
S3
S3w
hase Current
B
4.35
3.48
3.48
3.48
3.89
3.91
1
3
2
4
5.16
4.78
1
1
4.35
3.48
12
8
8
BC
3.48
3.48
12
11
10
8
C
5.16
3.48
3
2
3.48
1
1
2 - 3.5
4.35
10
Stub out
10
Stub out
Stub out
Stub out
Stub out
10
10
34.27
Total
No., type and size of wire Diameter of
2
RSC
( TW / mm )
2 - 3.5
15
2 - 3.5
15
2 - 3.5
15
2 - 3.5
15
2 - 3.5
15
2 - 3.5
15
2 - 3.5
15
2 - 3.5
15
2 - 3.5
15
2 - 3.5
15
2 - 3.5
15
2 - 3.5
15
2 - 3.5
15
2 - 3.5
15
2 - 3.5
15
34.73
34.79
C
BC
15
Panel Board LPB
Ckt. No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
Circuit Breaker Rating
F
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
T
15
15
15
15
15
15
15
15
15
15
15
15
15
15
15
15
Load Description
P
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
100w
10
9
6
9
9
12
10
9
8
10
10
10
Spare
Spare
Spare
Space
40w
Switches
S1
S2
S3
S3w
7
1
hase Current
B
4.4
3.9
1
1
1
1
2
1
2
2
2.6
3.9
1
1
1
1
3.9
5.2
4.4
4.4
3.5
4.4
1
1
1
4.4
4.4
10
10
10
27.1
Total
24.4
27.9
Panel Board LPC
Ckt. No.
Circuit Breaker Rating
Load Description
Phase Current
F
T
P
C.O 180 VA
AB
1
2
3
4
5
6
7
50
50
50
50
50
50
50
15
15
15
15
15
15
15
2
2
2
2
2
2
2
6
6
6
6
7
7
6
4.70
4.70
8
50
15
2
Spare
10.00
9
10
50
50
15
15
2
2
Spare
Space
CA
BC
No., type and size of wire ( Diameter of
2
RSC
TW / mm )
2 - 3.5
2 - 3.5
2 - 3.5
2 - 3.5
2 - 3.5
2 - 3.5
2 - 3.5
4.70
4.70
5.48
5.48
4.70
Stub Out
Stub Out
10.00
Total
24.10
15
15
15
15
15
15
15
19.40
10.96
Panel Board LPD
Ckt. No.
1
2
3
4
5
6
7
8
Circuit Breaker Rating
Load Description
Phase Current
F
T
P
C.O 180 VA
AB
50
50
50
50
50
50
50
50
15
15
15
15
15
15
15
15
2
2
2
2
2
2
2
2
7
6
6
6
6
6
Spare
Spare
5.48
4.70
CA
BC
No., type and size of wire ( Diameter of
RSC
TW / mm 2)
2 - 3.5
2 - 3.5
2 - 3.5
2 - 3.5
2 - 3.5
2 - 3.5
Stub Out
Stub Out
4.70
4.70
4.70
4.70
10.00
Total
20.18
10.00
19.40
CA
15
15
15
15
15
15
9.40
Panel Board PPA
Ckt. No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
Circuit Breaker Rating
Load Description
T
P
C.O 180 VA
AB
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
20
20
20
20
20
30
20
20
20
20
20
30
20
20
30
20
30
20
20
20
20
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
3
2
2
2
2
1 - HP ACU
1 - HP ACU
1 - HP ACU
1 - HP ACU
1.5 - HP ACU
1 - HP ACU
1 - HP ACU
1 - HP ACU
1 - HP ACU
1 - HP ACU
1 - HP ACU
1.5 - HP ACU
1 - HP ACU
1 - HP ACU
1 - HP ACU
1 - HP ACU
3 - HP ACU
Spare
Spare
Spare
Spare
8.00
8.00
Total
.,
Phase Current
F
BC
3Ø
8.00
8.00
10.00
8.00
8.00
8.00
8.00
8.00
8.00
10.00
8.00
8.00
10.00
8.00
9.60
10.00
10.00
10.00
58.00
10.00
60.00
56.00
9.60
2 - 3.5
2 - 3.5
2 - 3.5
2 - 3.5
2 - 3.5
2 - 3.5
2 - 3.5
2 - 3.5
2 - 3.5
2 - 3.5
2 - 3.5
2 - 3.5
2 - 3.5
2 - 3.5
2 - 3.5
2 - 3.5
2 - 3.5
Stub out
Stub out
Stub out
Stub out
Diameter of
RSC
15
15
15
15
15
15
15
15
15
15
15
15
15
15
15
15
15
No., type and size of wire Diameter of
RSC
( TW / mm 2)
2 - 3.5
15
2 - 3.5
15
2 - 3.5
15
2 - 3.5
15
2 - 3.5
15
2 - 3.5
15
2 - 3.5
15
2 - 3.5
15
2 - 3.5
15
2 - 3.5
15
2 - 3.5
15
2 - 3.5
15
Stub out
Stub out
Stub out
Panel Board PPB
Circuit Breaker Rating
Ckt. No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
Load Description
Phase Current
F
T
P
C.O 180 VA
AB
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
30
30
30
30
30
30
20
20
30
30
20
20
30
20
20
20
20
30
30
30
30
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
1.5 - HP ACU
1.5 - HP ACU
2 - HP ACU
2 - HP ACU
1.5 - HP ACU
1.5 - HP ACU
1 - HP ACU
1 - HP ACU
1.5 - HP ACU
1.5 - HP ACU
1 - HP ACU
1 - HP ACU
2 - HP ACU
1 - HP ACU
1 - HP ACU
1 - HP ACU
1 - HP ACU
Spare
Spare
Spare
Spare
10.00
10.00
Total
CA
BC
No., type and size of wire ( Diameter of
2
RSC
TW / mm )
2 - 3.5
2 - 3.5
2 - 3.5
2 - 3.5
2 - 3.5
2 - 3.5
2 - 3.5
2 - 3.5
2 - 3.5
2 - 3.5
2 - 3.5
2 - 3.5
2 - 3.5
2 - 3.5
2 - 3.5
2 - 3.5
2 - 3.5
Stub out
Stub out
Stub out
Stub out
12.00
12.00
10.00
10.00
8.00
8.00
10.00
10.00
8.00
8.00
12.00
8.00
8.00
8.00
8.00
10.00
10.00
10.00
100.00
10.00
54.00
15
15
15
15
15
15
15
15
15
15
15
15
15
15
15
15
15
46.00
Main Distribution Panel MDP
Panel
Ckt. No.
1
2
3
4
5
6
7
8
Phase Current
No., type and size of wire
Designation
AB
CA
BC
3Ø
(mm )
Diameter of
RSC
LPA
LPB
LPC
LPD
PPA
PPB
Spare
Spare
34.27
26.52
24.10
20.18
58.00
66.00
0.00
0.00
229.07
34.79
27.83
10.96
9.40
56.00
64.00
0.00
0.00
202.98
34.73
24.35
19.40
19.40
60.00
70.00
0.00
0.00
227.88
0.00
0.00
0.00
0.00
9.60
0.00
0.00
0.00
9.60
3 - 22 - TW
3 - 14 - THW
3 - 14 - THW
3 - 14 - TW
3 - 38 - THW
3 - 50 - THW
28
25
25
25
32
40
Total
2
Computations
I 3ØE
Allowance 20%
MATCC
Use :
= 9.6 + 1.73(229.01)
= 1.20 (406.26)
= 406.26 + 1.73(0.25)(12)
= 406.26 A
= 487.50 A
= 411.45
If exceeds 267 A initial load, 50% Allowance
2
3 - 325 mm THW (435 / 411.45 A) RS and 80mmØ
2
50mmØ
6 - 100 mm THW (220 / 205.73A)
2
40mmØ
9 - 50mm THW 145 / 137A
MROFCCPD = 30 + 1.73(229.01-12) + 9.6
= 415.47A (1.2)
= 498 A
Use : 500 AT / 600AF, 3P, ACB Type LA
Panel Board LPA
No., type and size of wire
Design Computation
(mm 2)
Diameter of
RSC
AT
AF
10 (100) / 230 = 4.35A
2 - 3.5 - TW
15.00
15
50
2
8(100) / 230 = 3.48A
2 - 3.5 - TW
15.00
15
50
3
8(100) / 230 = 3.48A
2 - 3.5 - TW
15.00
15
50
4
8(100) / 230 = 3.48A
2 - 3.5 - TW
15.00
15
50
5
8(100) / 230 = 3.48A
2 - 3.5 - TW
15.00
15
50
I 3ØE = 1.73 (34.79) = 60.26A
6
8(100) / 230 = 3.48A
2 - 3.5 - TW
15.00
15
50
MAFCC = 1.25 (60.26) = 75.35A
7
5(100)/230 + 4(0.43) = 3.89
2 - 3.5 - TW
15.00
15
50
8
9(100) / 230 = 3.91A
2 - 3.5 - TW
15.00
15
50
9
12(0.43) = 5.16A
2 - 3.5 - TW
15.00
15
50
10
11(100) / 230 = 4.78A
2 - 3.5 - TW
15.00
15
50
11
10(100) / 230 = 4.35A
2 - 3.5 - TW
15.00
15
50
12
8(100) / 230 = 3.48A
2 - 3.5 - TW
15.00
15
50
I 3ØE = 1.73 (27.83) = 48.20 A
13
12(0.43) = 5.16A
2 - 3.5 - TW
15.00
15
50
MAFCC = 1.25 (48.20) = 60.25A
14
8(100) / 230 = 3.48A
2 - 3.5 - TW
15.00
15
50
15
16
17
18
19
20
21
8(100) / 230 = 3.49A
10(100) / 230 = 4.35A
Spare = 10
Spare = 10
Spare = 10
Spare = 10
Space
2 - 3.5 - TW
2 - 3.5 - TW
2 - 3.5 - TW
2 - 3.5 - TW
2 - 3.5 - TW
2 - 3.5 - TW
2 - 3.5 - TW
15.00
15.00
Stub Out
Stub Out
Stub Out
Stub Out
15
15
50
50
use : 3 - 22mm2 TW (70 / 60.25A)
or 3 - 14mm2 THW (65 / 60.25)
MRCFCOPD : 70 AT / 100AF; 3P
No., type and size of wire
Diameter of
RSC
AT
AF
15.00
15
50
I 3ØE = 1.73(20.18) = 34.95
MAFCC = 1.25 (34.95) = 43.69 A
Ckt. No.
Phase Current I
1
MAFCC : Minimum Ampacity of Feeder Current Conductor
: at 125% of Full Load Current
MROFCOPD : Maximum Rating of Feeder Circuit Over Current Protective Device
LPA
32 mm Ø RSC
25 mm Ø RSC
MRCFCOPD : 70 AT / 100AF; 3P, ACB Molded Case Type EB
LPB
RSOR:
32 mm Ø RSC
25 mm Ø RSC
LPC
I 3ØE
MAFCC
use
or
MRCFCOPD
Panel Board LPB
= 1.73(24.10) = 41.74
= 1.25 (41.74) = 52.18A
RSOR:
25 mm Ø RSC
25 mm Ø RCP
2
: 3 - 14mm TW (55 / 52.18) A
2
3 - 14mm THW (65 / 52.18) A
: 50 AT / 50 AF, 3P, ACB Type EB
Ckt. No.
Phase Current I
1
10(100) / 230 = 4.35A
(mm )
2 - 3.5 - TW
2
9(100) / 230 = 3.91A
2 - 3.5 - TW
15.00
15
50
3
6(100) / 230 = 2.61A
2 - 3.5 - TW
15.00
15
50
4
9(100) / 230 = 3.91A
2 - 3.5 - TW
15.00
15
50
5
9(100) / 230 = 3.91A
2 - 3.5 - TW
15.00
15
50
6
12(100) / 230 = 5.22A
2 - 3.5 - TW
15.00
15
50
7
10(100) / 230 = 4.35A
2 - 3.5 - TW
15.00
15
50
8
9(100) / 230 = 3.91A
2 - 3.5 - TW
15.00
15
50
I 3ØE = 1.73(20.18) = 34.95
9
8(100) / 230 = 3.48A
2 - 3.5 - TW
15.00
15
50
MAFCC = 1.25 (34.95) = 43.69 A
10
10(100) / 230 = 4.35A
2 - 3.5 - TW
15.00
15
50
11
10(100) / 230 = 4.35A
2 - 3.5 - TW
15.00
15
50
12
10(100) / 230 = 4.35A
2 - 3.5 - TW
15.00
15
50
13
14
15
16
Spare = 10
Spare = 10
Spare = 10
Space
2 - 3.5 - TW
2 - 3.5 - TW
2 - 3.5 - TW
2 - 3.5 - TW
Stub Out
Stub Out
Stub Out
Stub Out
No., type and size of wire
Diameter of
RSC
AT
AF
15.00
15
50
2
RSOR:
use : 3 - 30mm2 TW (90 / 75.33A)
or 3 - 22mm2 THW (85 / 75.33A)
LPD
RSOR:
use : 3 - 14mm2 TW (55 / 43.69) A
or 3 - 8mm2 THW (45 / 43.69) A
25 mm Ø RSC
25 mm Ø RSC
MRCFCOPD : 50 AT / 50 AF, 3P
PPA
RSOR:
use : 3 - 14mm2 TW (55 / 43.69) A
or
25 mm Ø RSC
2
25 mm Ø RSC
3 - 8mm THW (45 / 43.69) A
MRCFCOPD : 50 AT / 50 AF, 3P
PPB
I 3ØE = 1.73(70) = 121.4 A
MAFCC = 121.24 + 0.25(1.73)(12) = 126.44A
use : 3 - 60mm2 TW (135 / 126.44) A
or 3 - 50mm2 THW (145 / 126.44) A
Panel Board LPC
RSOR:
40 mm Ø RSC
40 mm Ø RCP
MRCFCOPD : 30 + 1.73(70 - 12) = 130.46A
use : 125 AT / 225AF, 3P, ACB Type, Molded Case Type CA / CAB
Ckt. No.
Phase Current I
1
6(180) / 230 = 4.7A
(mm )
2 - 3.5 - TW
2
6(180) / 230 = 4.7A
2 - 3.5 - TW
15.00
15
50
3
6(180) / 230 = 4.7A
2 - 3.5 - TW
15.00
15
50
4
6(180) / 230 = 4.7A
2 - 3.5 - TW
15.00
15
50
5
7(180) / 230 = 5.48A
2 - 3.5 - TW
15.00
15
50
6
7(180) / 230 = 5.48A
2 - 3.5 - TW
15.00
15
50
7
6(180) / 230 = 4.7A
2 - 3.5 - TW
15.00
15
50
8
Spare = 10
2 - 3.5 - TW
Stub Out
6 - 100 mm2 THW
50 mm Ø
9
10
Spare = 10
Space
2 - 3.5 - TW
2 - 3.5 - TW
Stub Out
Stub Out
9 - 50mm 2 THW
MROFCOPD : 30 + 1.73(229.01- 12) + 9.6
= 415.47A x 1.2 = 498.57A
use: 500 AT / 600AF, 3P, ACB Type LA
40 mm Ø
2
MPB - Main Panel Board
I 3ØE = 9.6 + 1.73(229.01) = 406.26A
Allowance 20% = 1.20 (406.26) = 487.5A
MAFCC = 406.26 + 0.25(1.73)(12) = 411.45A
or = 9.6 + 1.73(229.01 - 12) + 1.25(12)(1.73) = 411.25A
use: 3 - 325 mm2 THW
RSOR: 80 mm Ø RSC
Panel Board LPD
No., type and size of wire
Ckt. No.
Phase Current I
(mm )
Diameter of
RSC
AT
AF
1
7(180) / 230 = 5.48A
2 - 3.5 - TW
15.00
15
50
2
6(180) / 230 = 4.7A
2 - 3.5 - TW
15.00
15
50
3
6(180) / 230 = 4.7A
2 - 3.5 - TW
15.00
15
50
4
6(180) / 230 = 4.7A
2 - 3.5 - TW
15.00
15
50
5
6(180) / 230 = 4.7A
2 - 3.5 - TW
15.00
15
50
6
6(180) / 230 = 4.7A
2 - 3.5 - TW
15.00
15
50
7
8
Spare = 10
Spare = 10
2 - 3.5 - TW
2 - 3.5 - TW
Stub Out
Stub Out
2
Panel Board PPA
Full Load
Ampere
Ampere
Current
Trip
Frame
Max Ampacity of Motor Br.
Ckt. Conductor
No, Type and Size of wire
Size of
Conduit mmØ
1
1 HP = 8A
2.5(8) = 20
50
1.25(8) = 10
2 - 3.5 - TW
15
2
8
20
50
1.25(8) = 10
2 - 3.5 - TW
15
3
8
20
50
10.00
2 - 3.5 - TW
15
4
8
20
50
10.00
2 - 3.5 - TW
15
5
10
2.5(10)=25 or 30
50
1.25(10) = 12.5
2 - 3.5 - TW
15
6
8
20
50
10.00
2 - 3.5 - TW
15
7
8
20
50
10.00
2 - 3.5 - TW
15
8
8
20
50
10.00
2 - 3.5 - TW
15
9
8
20
50
10.00
2 - 3.5 - TW
15
50
10.00
2 - 3.5 - TW
15
50
10.00
2 - 3.5 - TW
15
2 - 3.5 - TW
15
Ckt. No.
10
8
11
8
20
20
12
10
30
50
12.50
13
8
20
50
10.00
2 - 3.5 - TW
15
14
8
20
50
10.00
2 - 3.5 - TW
15
15
10
30
50
12.50
2 - 3.5 - TW
15
16
8
20
50
10.00
2 - 3.5 - TW
15
17
9.6
2.5(9.6)=24 or 30
50
1.25(9.6) = 12
2 - 3.5 - TW
15
18
10
30
50
12.50
2 - 3.5 - TW
15
19
10
30
50
12.50
2 - 3.5 - TW
15
20
21
10
10
30
30
50
50
12.50
12.50
2 - 3.5 - TW
2 - 3.5 - TW
15
15
Full Load
Ampere
Ampere
Current
Trip
Frame
Max Ampacity of Motor Br.
Ckt. Conductor
No, Type and Size of wire
Size of
Conduit mmØ
1
10
30
50
1.25(8) = 10
2 - 3.5 - TW
15
2
10
30
50
1.25(8) = 10
2 - 3.5 - TW
15
3
12
30
50
10.00
3 - 3.5 - TW
15
4
12
30
50
10.00
4 - 3.5 - TW
15
5
10
30
50
1.25(10) = 12.5
5 - 3.5 - TW
15
6 - 3.5 - TW
15
7 - 3.5 - TW
15
Panel Board PPB
Ckt. No.
6
7
8
20
50
10.00
8
8
20
50
10.00
8 - 3.5 - TW
15
9 - 3.5 - TW
15
9
8
20
50
10.00
10
8
20
50
10.00
10 - 3.5 - TW
15
11
8
20
50
10.00
11 - 3.5 - TW
15
12
10
30
50
12.50
12 - 3.5 - TW
15
13
8
20
50
10.00
13 - 3.5 - TW
15
14
8
20
50
10.00
14 - 3.5 - TW
15
15
10
30
50
12.50
15 - 3.5 - TW
15
16
8
20
50
10.00
16 - 3.5 - TW
15
17
9.6
2.5(9.6)=24 or 30
50
1.25(9.6) = 12
17 - 3.5 - TW
15
18
10
30
50
12.50
18 - 3.5 - TW
15
19
10
30
50
12.50
19 - 3.5 - TW
15
20
21
10
10
30
30
50
50
12.50
12.50
20 - 3.5 - TW
21 - 3.5 - TW
15
15
A
LPA Details
B
C
A
1
3
5
A
2
4
6
1
3
5
LPB Details
B
C
B
C
LPC Details
1
2
3
4
5
6
7
8
2
4
6
7
8
7
8
9
10
9
10
11
12 11
13
14 13
9
12
LPD Details
A
14
15
16 15
17
18
19
20
B
C
1
2
3
4
5
6
7
8
PPA Details
A
B
PPB Details
C
A
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
B
C
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
18
19
20
21
22
19
20
21
RISER D IAGRAM
PPB
LPD
LPB
GND
Service Drop
3Ø, 3 -wire
230V, 60 Hz
WG
GND
GND
PPA
LPC
LPA
MDP
M
Service KWHR Meter
(By others)
WIRE GUTTER
Riser : Single Line Diagram (Not to Scale)
2
Required Grounding conductor is N o. 50mm THW
2
3# - 325mm THW
in 80mm Ø RSCP (ungrounded conductor)
GROUNDING ELECTRODE CONDUCTOR FOR AC SYSTEM:
Size of Largest Service
2
Minimum Size of grounding Conductor / Equipment:
Size of Grounding Electrode
2
Entrance Copper (mm )
Conductor Copper (mm )
38 or smaller
38 - 50
60 - 80
80 - 200
200 - 325
325 - 500
8
14
22
30
50
60
Rating of Over Current
Protective Device
Size of mm copper
15
20
30
40
60
100
200
400
600
800
1000
1200
1600
2000
2500
3000
4000
2
3.5
5.5
5.5
5.5
8
14
30
38
50
60
80
100
125
200
200
250
2
Service Entrance Adequacy Standards
Conductor Size
Initial Load
Service
2
(A)
Switch (A)
AWG
mm
1 - 23
60
8
8
24 - 33
60
6
14
34 - 47
100
4
22
48 - 60
100
2
30
61 - 67
100
1
38
68 - 83
200
110
50
84 - 100
200
210
60
101 - 117
200
310
80
118 - 133
200
410
100
134 - 152
400
410
100
153 - 167
400
250
125
168 - 183
400
300
150
184 - 200
400
350
175
201 - 217
400
400
200
218 - 267
400
500
250
2
50mm
SOLID NEUTRAL COPPER BAR
2
No. 38mm Bare Copper wire / insulated
UNGROUNDED CONDUCTOR
GROUNDING CONNECTOR
MDP
DESIGN OF AN INDUSTRIAL PLANT
Maximum Number of Outlets Required:
Manufacturing Spaces
6
Storage Spaces
6
Offices
8
For every 40 watts fluorescent lamp, the input power (high power factor ballast)
52 watts
For every 40 watts fluorescent lamp, the current drawn by the ballast is
0.43 current
For ordinary 20 watts fluorescent lamp, the current drawn by the ballast is
0.23 current
For every convenience outlet (duplex), the power is
180 volt amp
Note: Provide at least one spare branch circuit for every five branch circuits.
Maximum Ampacity of Motor (Branch circuit conductor)
1.25 Full Load current
For Fused-Motors
3 Full Load current
Maximum Ampere rating of the Motor Circuit Breaker
2.5 Full Load current
That is for 1Ø and 3Ø motors with Full Load current less than 30 amperes
Maximum Ampere rating of the Motor Circuit Breaker
2 Full Load current
That is f or 3Ø motors with Full Load current more than 30 amperes
Note: Feeder conductors / branch circuit conductors for lighting, small appliance and similar loads shall be loaded not more than 80 of their ampacities.
1
= 1.25
0.8
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LOAD SCHEDULE FOR PANEL BOARD LP
Ckt. No.
LOAD DESCRIPTION
Volts
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
Duplex Convenient Outlet
Duplex Convenient Outlet
Duplex Convenient Outlet
Duplex Convenient Outlet
Duplex Convenient Outlet
Duplex Convenient Outlet
Freezer (5 1/4 HP each)
Freezer (5 1/4 HP each)
Fluorescent Lamps
Fluorescent Lamps
Freezer (5 1/4 HP each)
Freezer (5 1/4 HP each)
Fluorescent Lamps
Fluorescent Lamps
Fluorescent Lamp 24 I.L.
Fluorescent Lamp 32 I.L. 2
Fluorescent Lamp
Spare
Spare
Spare
230
230
230
230
230
230
230
230
230
230
230
230
230
230
230
230
230
230
230
230
Ckt. No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
Size of Homerun
2
Wire (mm )
2 - 3.5 TW
2 - 3.5 TW
2 - 3.5 TW
2 - 3.5 TW
2 - 3.5 TW
2 - 3.5 TW
2 - 3.5 TW
2 - 3.5 TW
2 - 3.5 TW
2 - 3.5 TW
2 - 3.5 TW
2 - 3.5 TW
2 - 3.5 TW
2 - 3.5 TW
2 - 3.5 TW
2 - 3.5 TW
2 - 3.5 TW
2 - 3.5 TW
2 - 3.5 TW
2 - 3.5 TW
Lighting
Outlet
Convenience
Outlet
Switch
8
8
7
6
6
6
5
5
18
14
2
6
5
5
12
11
18
18
11
2
7
8
6
5
Maximum Ampacity of the Feeder Current
= 1.25 (1.73)(largest phase current)
= 1.25(1.73)(53.37)
= 115.546 Amperes
Conduit (mm)
15Ø RSC
15Ø RSC
15Ø RSC
15Ø RSC
15Ø RSC
15Ø RSC
15Ø RSC
15Ø RSC
15Ø RSC
15Ø RSC
15Ø RSC
15Ø RSC
15Ø RSC
15Ø RSC
15Ø RSC
15Ø RSC
15Ø RSC
15Ø RSC
15Ø RSC
15Ø RSC
VA / Circuit
Ampere Load
1,440.00
1,440.00
1,260.00
1,080.00
1,080.00
1,080.00
3,335.00
3,335.00
936.00
728.00
3,335.00
3,335.00
624.00
624.00
1,448.00
1,764.00
1,144.00
2,300.00
2,300.00
2,300.00
6.26
6.26
5.48
4.70
4.70
4.70
14.50
14.50
4.07
3.16
14.50
14.50
2.71
2.71
6.30
7.67
4.97
10.00
10.00
10.00
Total
Load Per Phase
AB
6.26
6.26
CA
Circuit Breaker
BC
5.48
4.70
4.70
4.70
14.50
14.50
4.07
3.16
14.5
14.5
2.71
2.71
6.30
7.67
4.97
10.00
46.94
10
10
51.38
AT
20
20
20
20
20
20
30
30
20
20
30
30
20
20
20
20
20
20
20
20
AP
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
Pole
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
53.37
therefore use:
- 3 - 38mm2 THW (Ampacity = 125A)
- 32 mmØ RSCP
- 125AT / 200AF, 3P, 250V
LOAD SCHEDULE FOR PANEL BOARD PPA
Ckt. No.
LOAD DESCRIPTION
Volts
Phase
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
ACU, 1HP
Silent Cutter, 5HP
ACU, 1.5 Hp
ACU, 1.5 Hp
ACU, 2 Hp
ACU, 2 Hp
Stuffing Machine, 7.5 Hp
Grinder, 10 Hp
Chiller compressor, 3 Hp
Seamer, 1.5 Hp
Mince Master, 13 Kw
Vacuum sealer, 1/2 Hp
Bandsaw, 1 Hp
Linker & Air comp, 2 - 1/3 Hp
Plastic sealer, 2 - 300w
Silent Cutter, 5HP
Spare
Spare
230
230
230
230
230
230
230
230
230
230
230
230
230
230
230
230
230
230
1
1
1
1
1
1
3
3
3
3
3
3
1
1
1
1
1
1
VA per circuit
1,840.00
6,440.00
2,300.00
2,300.00
2,760.00
2,760.00
8,764.00
10,755.00
3,585.00
1,992.00
19,121.00
7,970.00
1,840.00
1,656.00
600.00
6,400.00
2,300.00
2,300.00
Ampere per
circuit
8
28
10
10
12
12
22
27
9
5
48
2
8
7.2
2.6
28
10
10
Load Per Phase
AB
8
28
CA
BC
Circuit Breaker
3Ø
10
10
12
12
22
27
9
5
48
2
8
7.2
2.6
28
10
10
Total
51.2
50.6
Ampere per
circuit
AB
CA
44
AT
20
70
30
30
30
30
50
70
20
20
100
20
20
20
20
70
30
30
AP
50
50
50
50
50
50
50
100
50
50
100
50
50
50
50
100
50
50
Size of Homerun
Pole
2
2
2
2
2
2
3
3
3
3
3
3
2
2
2
2
2
2
2
Wire (mm ) Conduit (mm)
2 - 3.5 TW
15Ø RSC
2 - 8.0 TW
20Ø RSC
2 - 3.5 TW
15Ø RSC
2 - 3.5 TW
15Ø RSC
2 - 3.5 TW
15Ø RSC
2 - 3.5 TW
15Ø RSC
3 - 5.5 TW
15Ø RSC
3 - 8.0 TW
20Ø RSC
3 - 3.5 TW
15Ø RSC
3 - 3.5 TW
15Ø RSC
3 - 22 TW
25Ø RSC
3 - 3.5 TW
15Ø RSC
2 - 3.5 TW
15Ø RSC
2 - 3.5 TW
15Ø RSC
2 - 3.5 TW
15Ø RSC
2 - 8.0 TW
20Ø RSC
2 - 3.5 TW
15Ø RSC
2 - 3.5 TW
15Ø RSC
Pole
3
3
2
2
2
2
2
2
2
2
2
2
2
2
2
Wire (mm ) Conduit (mm)
3 - 3.5 TW
15Ø RSCP
3 - 3.5 TW
15Ø RSCP
2 - 8.0 TW
20Ø RSCP
2 - 5.5 TW
15Ø RSCP
2 - 3.5 TW
15Ø RSCP
2 - 5.5 TW
15Ø RSCP
2 - 5.5 TW
15Ø RSCP
2 - 5.5 TW
15Ø RSCP
2 - 3.5 TW
15Ø RSCP
2 - 3.5 TW
15Ø RSCP
2 - 8.0 TW
20Ø RSCP
2 - 3.5 TW
15Ø RSCP
2 - 3.5 TW
15Ø RSCP
2 - 3.5 TW
15Ø RSCP
113
Minimum Ampacity of the Motor Feeder Conductor
= I3Ø + 1.73(largest phase current) + 0.25 (largest full load current)
= 113 + 1.73(51.2) + 0.25(48)
= 213.68 Amperes
Wire: Use 3- 100mm2 THW
Conduit: Use 50mmØ RSCP
Maximum ampere rating of the Feeder Circuit Breaker:
= Rating of largest C.B. + Full Load line current of the other motors
= 100 + (113 - 48) + 1.73(51.2)
= 253.68 Amperes
Use: 250 AT / 400AF
LOAD SCHEDULE FOR PANEL BOARD PPB
Ckt. No.
LOAD DESCRIPTION
Volts
Phase
1
2
3
4
5
6
7
8
9
10
11
12
13
14
Seamer, 1/2 Hp
Seamer, 1/2 Hp
Mixer, 5 Hp
Silent Cutter, 3 Hp
Freezer, 2 - 1/3 Hp
Silent cutter, 3 Hp
Grinder, 3 Hp
Grinder, 3 Hp
Slicer, 2 - 1/3 Hp
Slicer, 2 - 1/3 Hp
Mixer, 5 Hp
Plastic Sealer, 2 - 300w
Spare
Spare
230
230
230
230
230
230
230
230
230
230
230
230
230
230
3
3
1
1
1
1
1
1
1
1
1
1
1
1
VA per circuit
1,992.00
1,992.00
6,440.00
3,910.00
1,656.00
3,910.00
3,910.00
3,910.00
1,656.00
1,656.00
6,440.00
600.00
2,300.00
2,300.00
5
5
28
17
7.2
17
17
17
7.2
7.2
28
26
10
10
Total
Load Per Phase
BC
Circuit Breaker
3Ø
5
5
28
17
7.2
17
17
17
7.2
7.2
28
26.00
59.40
78.20
10
10.00
54.00
10.00
AT
20
20
70
50
20
50
50
50
20
20
70
20
20
20
AP
50
50
100
50
50
50
50
50
50
50
100
50
50
50
Size of Homerun
MAFCC = 10 + 1.73(59.4-28) + 1.25(1.73)(28)
= 126.73 Amperes
Use : 3 - 50mm2 THW, 145A / 126.73 A in 40mmØ RSCP
MROFCOPD = 70 + 1.73(31.4) + 10
Use : 150 AT / 200AF, 3P, 250V C.B.
=
=
10+1.73*(78.2)+0.25*28*1.73
157.396
=
=
(10+1.73*78.20)*1.25+0.25*28*1.73
193.7175
SUMMARY OF LOADS MDP
LOAD DESCRIPTION
Volts
Phase
Total VA
LP
PPA
PPB
Meat Cutter
Meat Cutter
230
230
230
230
230
3
3
3
3
3
25,068.00
80,850.00
42,672.00
37,647.00
37,647.00
Load Per Phase
AB
46.94
51.20
59.40
Total
157.54
BC
51.38
50.60
54.80
CA
53.37
44.00
54.00
156.78
151.37
3Ø
113.00
10.00
118.13
118.13
uit Breaker Rating
AT
125
250
150
250
250
AF
200
400
200
400
400
Type and Size of wire
Pole
3
3
3
3
3
2
3 - 38mm THW
2
3 - 100mm THW
2
3 - 50mm THW
2
3 - 60mm THW
2
3 - 60mm THW
Size of Conduit
30mmØ RSCP
50mmØ RSCP
40mmØ RSCP
40mmØ RSCP
40mmØ RSCP
359.26
Note : The Efficiency of the Meat Cutter is assumed to be 85% and the power factor is assumed to be 80%
32 (1000)
Meat Cutter I FL =
= 118.13
1.73 (230)(0.85)(0.8)
MAFCC = 1.25(118.13)
=147.66 Amperes
Use : 3 - 60mm2 THW, (160A / 147.66A) in 40mmØ RSCP
MROFCOPD = 2(118.12)
= 236.26 Amperes
Use : 250AT / 400AF, 3P 250V motor branch circuit breaker
MDP:
Minimum Ampere = 1.73(157.54) + (359.26 - 118.13) + 1.25(118.13)
= 662 Amperes
Use : 2 sets of 3 - 250mm2 THW (750 / 622A), in 80mmØ RSCP
Maximum ROFCOPD = 250 + (359.26 - 118.13) + 1.73(157.54)
= 763.98 Amperes
Use : = 800AT / 800Af, 3P 250V Main Feeder C.B.
COMPUTATION
PPA CKT.
NO
AMPERE TRIP, AT
NONADJUSTABLE
TRIP C.B
A.F
AMPERE TRIP (AT)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
2.5 x 8 = 20 A
2.5 x 28 = 70 A
2.5 x 10 = 25 A
2.5 x 10 = 25 A
2.5 x 12 = 30 A
2.5 x 12 = 30 A
2.5 x 22 = 55 A
2.5 x 27 = 67.5 A
2.5 x 9 = 22.5 A
2.5 x 5 = 12.5 A
2.5 x 48 = 96 A
2.5 x 2 = 5 A
2.5 x 8 = 20 A
2.5 x 7.2 = 18 A
2.5 x 2.6 = 6.5 A
2.5 x 28 = 70 A
2.5 x 10 = 25 A
2.5 x 10 = 25 A
20
70
30
30
30
30
50
70
20
20
100
20
20
20
20
70
30
30
50
100
50
50
50
50
50
100
50
50
100
50
50
50
50
100
50
50
1.25 x 8 = 10 A
1.25 x 28 = 35 A
1.25 x 10 = 12.5 A
1.25 x 10 = 12.5 A
1.25 x 12 = 15 A
1.25 x 12 = 15 A
1.25 x 22 = 27.5 A
1.25 x 27 = 33.75 A
1.25 x 9 = 11.25 A
1.25 x 5 = 6.25 A
1.25 x 48 = 60 A
1.25 x 2 = 2.5 A
1.25 x 8 = 10 A
1.25 x 7.2 = 9 A
1.25 x 2.6 = 3.25 A
1.25 x 28 = 35 A
1.25 x 10 = 12.5 A
1.25 x 10 = 12.5 A
LP DETAILS
A
B
C
Wire Size
(mm2)
2 - 3.5 TW
2 - 8 TW
2 - 3.5 TW
2 - 3.5 TW
2 - 3.5 TW
2 - 3.5 TW
3 - 5.5 TW
3 - 8.0 TW
3 - 3.5 TW
3 - 3.5 TW
3 - 22 TW
3 - 3.5 TW
2 - 3.5 TW
2 - 3.5 TW
2 - 3.5 TW
2 - 3.5 TW
2 - 3.5 TW
2 - 3.5 TW
PPA
DETAILS
B
C
A
Conduit (mm)
Ø RSCP
15
20
15
15
15
15
15
20
15
15
25
15
15
15
15
15
15
15
Minimum Ampacity of the Feeder Conductor:
= 1.25(1.73)(largest phase current)
= 1.25(1.73)(53.37)
= 115.546 Ampere
Wire Use : 3 - 38mm2 THW (Ampacity = 125 A)
Conduit Use : 32 mmØ RSCP
Feeder Circuit Breaker for LP, use: 125 AT / 200AF, 3P, 250V
Computation for AT
1.) 2.5 x 6.26 = 15.65………… 20
3.) 2.5 x 5.43 = 13 .7…………… 20
12.) 2.5 x 14.5 = 36.25………… 36.25
Note:
Maximum no. of branch circuit in one panel board is 21.
A
PPB
DETAILS
B
C
250AT / 400 AF, 3P 250V
125 AT / 200 AF
1
2
1
2
3
4
3
4
5
6
5
6
7
8
7
8
9
10
11
12
13
14
15
16
17
18
9
19
10
11
12
13
14
15
16
17
18
1
2
3
4
5
6
7
8
9
10
11
12
13
14
20
COMPUTATION
PPB
COMPUTATION
AT
AF
1
2
3
4
5
6
7
8
9
10
11
12
13
14
2.5 (5) = 12.5
2.5 (5) = 12.5
2.5 (28) = 70
2.5 (17) = 42.5
2.5 (7.2) = 18
2.5 (17) = 42.5
2.5 (17) = 42.5
2.5 (17) = 42.5
2.5 (7.2) = 18
2.5 (7.2) = 18
2.5 (28) = 70
2.5 (2.60 = 6.5
Spare = 10
Spare = 10
20
20
70
50
20
50
50
50
20
20
70
20
20
20
50
50
100
50
50
50
50
50
50
50
100
50
50
50
WIRE SIZE mm
1.25(5) = 6.25
1.25(5) = 6.25
1.25(28) = 35
1.25(17) = 21.25
1.25(7.2) = 9
1.25(17) = 21.25
1.25(17) = 21.25
1.25(17) = 21.25
1.25(7.2) = 9
1.25(7.2) = 9
1.25(28) = 35
1.25(2.6) = 3.25
1.25(10) = 12.5
1.25(10) = 12.5
2
2 - 3.5 TW
2 - 3.5 TW
2 - 8.0 TW
2 - 5.5 TW
2 - 3.5 TW
2 - 5.5 TW
2 - 5.5 TW
2 - 5.5 TW
2 - 3.5 TW
2 - 3.5 TW
2 - 8.0 TW
2 - 3.5 TW
2 - 3.5 TW
2 - 3.5 TW
MAFCC = 10 + 1.73(59.4 - 28) + 1.25(1.73)(28)
= 126.73 Amperes
Use : 3 - 50mm2 THW, 145 / 126.73A
Conduit : 40 mmØ RSCP
MROFCOPD = 70 + 1.73(59.4 - 28) + 10
= 134.39 Amperes
Use : 150AT / 200AF, 3P 250V FCB
L RISER DIAGRAM
To 230V, 3Ø supply
2
2 sets of 3 - 250 mm THW in
80mmØ RSCP for each set
2
3 - 60mm 40mmØ RSCP
M
250AT / 400 AF
LP
250 AT / 400 AF
3P, 250V
PPA
PPB
MDP
125 AT / 200AF
150 AT / 200 AF, 3P, 250V
ELECTRICAL PLAN :
Specification written on an Electrical Plan should indicate:
1. That the design is done in accordance with the Philippine Electrical Code (PEC) and all electrical works shall comply with the provisions of all
authorities having jurisdiction on the use of electrical power.
2. The nature of the service including voltage, phase and frequency.
3. The type of approved wiring to be used in installing service entrance, feeders, subfeeders , branch circuit conductors, remote control system, fire
protection, signal and communication system.
4. All other aspects and details that the designer and the owner would want to be done in the actual construction of the project.
Example:
1. Work hereunder shall comply with the latest edition of the Philippine Electrical Code, The National Building Code, Municipal or City ordinances, office
of the Municipal or City Electrician, National Power Corporation and Meralco.
2. Type of service shall be 220/110V, 1 phase (single phase) , 3-wire system, 60 Hz and there shall be only one service drop to the building.
3. Method of wiring shall be in RMC for both exposed and embedded work with proper fittings and supports. In cases where concealed conduits wiring is
impracticable to use metal molding may be applied.
4. All wall outlets shall be installed at the following heights above finished floor level, unless otherwise noted:
a. Wall Switches
1.20 meters
b. Convenience Outlet
0.30 meters
c. Convenience outlet above counter
0.15 meters
d. Night Light outlet
0.30 meters
e. Air-conditioning outlet (to be determine by Engr. Or Arch-in-charge)
f. Electrical clock outlet
2.75 meters
g. Electrical interval timer outlet
2.50 meters
h. Telephone Outlet
0.30 meters
I. Vibrating bell outlet
0.30 meters
j. Call bell outlet
0.30 meters
k. Fire alarm station outlet
1.50 meters
l. Fire alarm bell outlet
2.75 meters
m. Master Timer programmer outlet
1.00 meters
n. Master timer programmer outlet
1.00 meters
o. Bundy clock outlet
1.00 meters
p. Chime bell outlet
2.50 meters
q. Panelboard and safety switches
1.35 meters
r. Service kilowatt-hour meter
1.60 meters
5. All materials and equipment shall be new and approved type for both location and purpose intended.
2
2
6. All lightning and convenience receptacle circuit shall be wired with not less than 2mm and 3.5mm copper respectively unless otherwise indicated on
the plan.
7. Lightning and power panelboard shall be circuit breaker type, surfaced or flushed mounted or as indicated in plan. Door shall be provided with locked
and grilled key. A line circuit directory card and holder shall be provided on face of door.
8. Whenever required and necessary, Pull boxes and junction boxes of proper sizes shall be installed at convenient and inconspicuous locations
although such boxes are not shown on the plans nor mentioned in the specifications.
9. All outdoor installations shall be weatherproof type.
10. All electrical works shall be done under the direct and immediate supervision of a duly lic ensed Electrical Engineer.
LEGEND / SYMBOLS:
The Legend or Symbols shall show configurations and figures of devices and equipment used. Standard Electrical Symbols can be obtained from page
732 appendix of Philippine Electrical Code (PEC).
LOCATION PLAN:
Location or site plan. W ith proposed structures and owners land, drawn to appropriate metric scale shall show:
1. Bordering areas showing public or well-drawn streets.
2. Location of service drop, service equipment and nearest pole of the utility company furnishing electrical energy.
3.Clearance of the path or run of service drops and service entrance sites to adjacent existing or proposed structures.
RISER DIAGRAM:
Consist of the schematic diagram of service entrance, feeders and branch circuits. This indicates:
1. The number of branch circuits, the size of conductors, size of conduit and protection for each branch circuits.
2. The sizes of feeders, its conduit and feeders protection.
3. The type of service, size of service entrance conductor, conduit and main protection device.
TITLE BLOCK:
The Title Block or Nameplate of plans and drawings shall be a standard strip of 40mm high at the bottom of each sheet of the plan.
Example:
2.
1
Proposed Electrical
Plan of a Single Family
Dwelling Phase II, Palmera
Subd., Q.C.
3
Ground and Second
Floor Electrical Plan, Riser
Diagram, Location Plan,
Legend.
5
9
7
1. Constructors Logo : Name and address of constructors company
2. Name of Project.
3. Sheet Contents.
4. Name and Address of owner.
Example: Felimon C. Sangcap
60 Dulong Ilog, Candaba
Pampanga
5. Drawn By
6. Checked By
7. Designed By
8. Scale
9. Name of Professional Electrical Engineer
10. Registration No.
11. PTR No.
12. Res Cert No.
13. TIN No.
14 Sheet No.
ELECTRICAL LIGHTNING AND POWER LAYOUT:
Electrical layout for each floor of the building shall indicate the location of:
1. Location of lightning outlets.
2. Location of convenience outlet.
3. Location of switches with their corresponding symbols.
4. Location of special purposed outlets or fixed appliance with their corresponding symbols.
5. Location of outlets for Air Conditioning Units (ACU).
6. Location of Service Equipment and / or disconnecting means.
7. Location of Service kilowatt-hour meter.
SCHEDULE OF LOADS AND COMPUTATION:
Schedule of loads in tabulated form shall indicate:
1. Motor Loads:
a. Motor as numbered or identified in power layout.
b. Type of motor
c. HP / KW / KVA Rating
d. Voltage Rating
e. Full load current rating
g. number of phases
6
4
8
10
11
12
13
14
2. Lightning Loads:
a. Panel as numbered in the Riser Diagram
b. Circuit designation number
c. number of lightning outlets in each circuit
d. Number of switches in each circuit
e. Number of convenience outlets
f. Voltage of circuit
g. Fuse rating or trip rating of circuit protective device
3. Other Loads:
a. Designation number on plan
b. description of load
c. Classification of service duty
d. Rating in kilovolt ampere (KVA) or kilowatt (KW)
e. Phase loading indicating full load line current
f. Voltage rating
ELECTRICAL ESTIMATION GUIDE:
1. Prepare paper, pencils, scale and rulers. Mark papers indicating the panel no., ckt. No and the location of the ckt. Run.
2. Study plans, drawings and specifications:
2.1 Coordinate with Civil, Mechanical and Architectural Estimators about the following:
2.1.1 height between floors
2.1.2 drop ceiling and ceiling supports
2.1.3 height between finished floors and ceilings
2.1.4 major beams and columns thru which conductors may not pass
2.1.5 other architectural / civil / mechanical / drawings indicating positions of lights, special outlets or aircon unit
equipment.
2.2 Check and make a physical count of the following:
2.2.1 lighting fixture - no. of each type of fixture
2.2.2 convenience outlet duplex
2.2.3 special outlets
2.2.4 panel boards - make a complete description of each panel board. The description includes:
a. main breaker ratings or lugs only
b. no. of branches per ampere trip
c. KAIC ratings
2.2.5 Other electrical equipment to be supplied by contractor
2.3 Study carefully the circuit runs and the riser diagram together with the schedule load.
3. Determine the approximate length of wire and conduct per circuit.
3.1 For the conduit - each ckt measure the length fromthe last outlet to the panel using the scale. The trace of the route must be followed
as per drawings.
3.2 For the wire- measure the length between outlet and the length shall be multiplied by the number of wires. The sum of the products
(length x the number of wires) shall be approximate length of the wire.
3.3 Sum up the total length of conduit per size and divide by 150 to get the no. of rolls. Round off and add 10%.
3.4 Sum up the total length of wire for each size and divide by 150 to get the no. of rolls. Round off and add 10%.
3.5 Set aside the papers and data temporarily.
4. Determine the approximate length of wire and conductor for the panel homerun to the main panel or main distribution panel.
4.1 Conduits - measure the length of the run. Check the shortest possible route and avoid obstructions. The total length divide by 3 and
add 5%.
4.2 Conduits not embedded in concrete shall be firmly supported and fastened in place every 3.0m and within 0.91m of each outlet box or
cabinet.
4.3 Conduits shall have no more than four (4) 90 degrees bends in any run. When it becomes necessary to have more than 4 90 degrees
bends, an intermediate pull box shall be installed to facilitate pulling of wires and cables.
4.4 Wire - multiply the length of conductor by the following constants:
a. 2 for two wire single phase
b. 3 for two wire single phase with neutral
c. 3 for three wire 3-phase
d. 4 for three phase, four wires
5. Boxes
5.1 Octagonal Boxes - provide one box for each lighting fixture.
5.2 Utility box 4" x 2" - provide one box for each switch; duplex outlet or special outlet (small).
5.3 Square box 4" - provide one box if the conduits terminating exceed 4 conduits or special big outlet.
5.4 Square box 4 11/16" - provide one box for 1 inch diameter conduits or for special purpose outlets. Also provide one box for multiple (6
or more) terminations.
5.5 Pull Boxes - provide one box for every 18 meters per conduits length depending upon the length of run. Other pull boxes may be
designated by plans. Check with the designer / consultant about sizes.
6. Fittings
6.1 For PVC pipes
6.1.1 couplings - provide 1 coupling for every length plus 1 coupling for every termination.
6.1.2 elbows - provide 1 - 90 degrees elbow for every turn f or sizes of 32mm (1 1/44) and above.
6.1.3 cement - provide one can for every 10 lengths of conduit.
6.1.4 end bells - provide 1 for every terminations.
6.2 For RSC conduits
6.2.1 couplings - provide 1 additional coupling for every 5 lengths.
6.2.2.elbows - provide one 90 degrees elbow for every 90 degrees turn for sizes of 25mm (1") diameter above.
6.2.3 locknut and bushings - provide one pair for every termination.
6.3 For Electrical Metallic Tubing (EMT)
6.3.1 Couplings - 1 set screw coupling for every length.
6.3.2 Elbows - use on-site bended EMT.
6.3.3 Adapters with locknuts and bushing - for every termination is an adapter and 1 pair of locknut and bushing.
6.4 Straps - two (2) straps for every length of conduit. In sizes of 25 mm (1") diameter and above use clamps or screwed on clamps,
especially for RSC or EMT conduits.
6.5.1 Wire trays / cable trays - check with the drawings and the consultant / designer.
6.5.2 Cable troughs / duets - check with drawings especially that the drawing may have specific sizes.
6.5 Every cable riser splicing shall be provided with pullbox and cable support (for exposed conduit provide clamps every 1.5m).
6.6 For every straight cable riser shall be provided with pullbox and cable support every four floors.
6.7 Pullbox shall be provided with cable support.
Conduit Riser
(refer to riser for size)
Pull Box
Pullbox Ga#16 (size
as required)
Hard rubber
insulation
Anchor
Bolt
Unistrut
Channel
Wires and cables
(as per load
schedule)
Cable Stopper
(Typical)
Pullbox Cover
Provision for padlocking
Junction Box
To Lighting Fixture or Box
Flexible Metallic Conduit
Strap
IMC or Flexible
Metallic Conduit
Double Locknut and Bushing
Wire Nut
Junction / Utility / Square or Pullbox
7. Other considerations.
7.1 For lighting fixtures - add 1 meter (multiply by number of wires per conduit) of wire for every termination or lighting fixture.
Slab
Support
Octagonal Box
Pipe**
** PVC if embedded, IMC or
EMT if exposed
Floor
Elevation
Drop Height
Ceiling Height
= Ceiling Height +
= As per Architect Specification
consideration
Flexible Metallic Conduit
Additional 1 meter consideration
Lighting
Fixture
Mounting - As per Architecture Specification
Height
Additional 1 meter
consideration per wire
Floor
7.2 For convenience outlets
a. Add 0.8 meter for every c.o. to the length of pipe and 1 meter of wire for every termination.
b. Add 0.4 meter above the height of counters if the c.o. is above the counter in addition to the height of the counter. Also
1 meter of wire for every termination.
Conven ience Outlet
Add 1 meter consideration per wire
Utility Box**
2
** For wires up to 5mm only. Use Square Box if more than 5
Add 0.8 meters
consideration
Mounting = 0.3 meters (as per PEC)
Height unless otherwise specified
Floor
Elbow
Conven ience Outlet (Coun tertop)
Add 1 meter consideration per wire
Utility Box**
counter
consideration
Add 0.4 meters
consideration
Mounting = 0.15 meters (as per PEC)
Height unless otherwise specified
Add 0.8 meters
consideration
Countertop = As per Architectural
Height Specification
Floor
floor
Elbow
Switches
Slab
Ceiling
Pipe**
** PVC if embedded, IMC or
EMT if exposed
Floor
Elevation
Support
Octagonal Box
Splice
Drop = Floor Elevation minus Mounting Height
Height
Utility Box
Add 0.8 meter consideration
Mounting = 1.3 meters (as per PEC)
Height unless otherwise specified
Additional 1 meter
consideration per wire
Floor
7.3 For homeruns terminating at panel boards, add 3 meters of wire (multiply by the nu mber of wires) for every circuit.
Slab
Pipe**
** PVC if embedded, IMC or
EMT if exposed
Support
Octagonal Box
Ceiling
Drop = Floor Elevation minus Mounting Height
Height
Add 0.8 meter consideration
Utility Box
Floor
Elevation
Mounting Height 2
= 0.45 m minimum
distance from floor
Mounting = 1.8 meters from the center (as per PEC)
Height unless otherwise specified
Additional 3 meter
consideration per wire
Floor
7.4 Provide an empty conduit for every spare circuit per panel.
7.5 Normally the electronic and communication circuits will be in separate sheets and have an ECE estimate.
7.6 Provide connector for every termination #6 up.
8. Summarize the list of materials as follows:
8.1 Conduits - total of each size / type
8.2 Fittings - total of each type size
8.3 Boxes - total for each type / size
8.4 Panels - per panel and lowest canvassed price.
8.5 Wires - total length for each wire size
8.6 Connectors - (solder less type) total termination of each size for wire size #6 AWG and above.
8.7 Tape - 1 roll PVC tape for 100 meters of wire plus 1 roll of rubber tape for every 200 meters of wire.
9. Costing:
9.1 get the unit cost for every item and deduct all discounts.
9.2 From the total cost add a 5% to 10% mark-up.
9.3 For all other materials like ducts, panels, transfer switches, safety switches, starters etc. - get the price from the fabricator net (less
discounts) and add 5% mark-up.
10. Preparation of Bid or Asking Price
10.1 Materials Cost
Conduits Fitting Boxes
Wires and Wiring Devices
Lighting Fixtures
Safety Devices
Service Entrance and Mains
Others
10.2 Labor Cost (subject for interpretation)
10.2.1 If Materials are imported
a. Labor Cost is 20% of sub-total A
b. Supervision is 3% of Sub-total A
c. Mark-up is 1.25% of Sub-total A
10.2.2 If the conduits and most materials are locally available
a. Labor cost is 25% to 30% of sub-total A
b. Supervision cost is 4% to 5% of subtotal A
c. Mark-up cost is 2% of subtotal A
10.3 Contingencies - an allowance of 5% to 7% of the total cost of materials and labor.
10.4 Overhead - this includes the cost of transportation, office staff, tools and equipment depreciation, paper and office supplies,
representation and insurance cost of money.
'- normally 7% to 10% of the cost of materials is the cost of overhead.
10.5 Permits - shows the plans to the municipal electrical engineer or his assistant and request for an estimate, Add 5% to cover the
exigencies.
10.6 a. the sum of the cost as computed is sections 10.1 to 10.5 is multiplied by 0.03 to get the contractors tax.
b. Add the contractors tax to the sum of sections 10.1 to 10.5 and round-off. This will be your bid price.
11. Concrete encasement / Pipe Chase / Sleeve Sealant Details
To compute for concrete encasement (same with block-outs) use the following:
11.1 Determine the size of the conduit to be embedded
11.2 Determine the length of the conduit to be embedded.
11.3 Obtain the volume of concrete to be used. Use the following spacing:
0.05 to 0.075m = Distance between the edge of the conduit to the edge of the concrete
0.05m = Distance between 2 conduit
A of Blockout = A of Box - (A of conduit x
No. of conduits)
V of Concrete encasement = Length of Pipe
x A of Blockout
0.05m
Conduit
size
Conduit
size
0.05m
Telephone Wires and Cable
(Typical)
Concrete Slab
A
25 mm
Silicon Sealant or Intumescent putty
"Specseal" or "Hilti"
Finished Floor Level
Note:
Use Metallic Pipe for all Pipe Sleeves
Wires and Cables
(Typical)
Fiberglass or
Mineral Wool insulation
PLAN
Silicon Sealant or
Intumescent Putty
"Specseal" or "Hilti"
SECTION A
Electrical Pipe Chase or large
openings through concrete walls
and slabs
Pipes
Concrete Slab
B
IMC Pipe (Typical)
Fire Rated Mortar
"Specseal" or "Hilti"
Finished Floor Level
Fire Rated Mortar "Specseal" or "Hilti"
installed to a minimum of 115mm depth
PLAN
115mm (min)
Electrical Pipe Chase or
large opening through
concrete walls and slabs
SECTION B
C
Concrete Slab
Fiberglass or Mineral
wool insulation
Small opening through
concrete wall or slab
IMC Pipe (Typical)
Intumescent putty or sealant
"Specseal" or Hilti"
Intumescent Putty or Sealant
"Specseal" or "Hilti"
SECTION C
PLAN
3
11.4 Obtain cost (use PhP 4000 / m to determine cost. Ask civil group for update on price. Price contains both material and labor cost).
WIRING SCHEDULE:
1 PHASE, 2W+G
ITEM NO. C.B. TRIP
S1
S2
S3
S4
S5
S6
S7
S8
S9
S10
S11
S12
S13
15
20
30
40
50
60
70
90
100
125
150
175
200
SET
1
1
1
1
1
1
1
1
1
1
1
1
1
WIRING SCHEDULE:
15
20
30
40
50
60
70
90
100
125
150
175
200
225
250
300
350
400
500
600
800
1000
1200
1600
2000
2500
SIZE (mm2)
LINE
G
2
2
3.5
3.5
5.5
5.5
8
5.5
14
8
22
8
22
8
30
8
38
14
60
22
80
22
100
30
125
30
RACEWAY
SIZE (mm)
METAL
PVC
15
20
15
20
15
20
25
25
25
32
40
40
40
40
40
40
50
50
50
63
50
63
50
75
65
75
SIZE (mm2)
LINE
G
2
2
3.5
3.5
5.5
5.5
8
5.5
14
8
22
8
22
8
30
8
38
14
60
22
80
22
100
30
125
30
150
30
200
30
250
30
100
30
125
30
200
30
125
30
200
30
200
30
125
30
200
30
200
30
200
30
RACEWAY
SIZE (mm)
METAL
PVC
15
20
15
20
15
20
25
25
25
32
32
40
32
40
40
40
50
50
50
63
65
63
65
75
80
75
80
90
90
90
100
110
65
75
80
75
90
90
80
75
90
90
90
90
80
75
90
90
90
90
90
90
3 PHASE, 3W+G
ITEM NO. C.B. TRIP
T1
T2
T3
T4
T5
T6
T7
T8
T9
T10
T11
T12
T13
T14
T15
T16
T17
T18
T19
T20
T21
T22
T23
T24
T25
T26
CONDUCTORS
QUANTITY
LINE
G
2
1
2
1
2
1
2
1
2
1
2
1
2
1
2
1
2
1
2
1
2
1
2
1
2
1
SET
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
2
2
2
3
3
4
6
6
8
10
CONDUCTORS
QUANTITY
LINE
G
3
1
3
1
3
1
3
1
3
1
3
1
3
1
3
1
3
1
3
1
3
1
3
1
3
1
3
1
3
1
3
1
3
1
3
1
3
1
3
1
3
1
3
1
3
1
3
1
3
1
3
1
NEC Table 1
In Raceway
Size
Copper
o
In Free Air
Aluminum
o
o
Copper
o
o
Alum
o
AWG & MCM
75 C
90 C
75 C
90 C
75 C
90 C
14
20
25
30
35
12
25
30
20
25
35
40
10
35
40
30
35
50
55
8
50
55
40
45
70
80
6
65
75
50
60
95
105
4
85
95
65
75
125
140
3
100
110
75
85
145
165
2
115
130
90
100
170
190
1
130
150
100
115
195
220
1/0
150
170
120
135
230
260
2/0
175
195
135
150
265
300
3/0
200
225
155
175
310
350
4/0
230
260
180
205
360
405
250
255
290
205
230
405
455
500
380
430
310
350
620
700
NEC Table 2
Ampacity Correction Factor
Ambient
o
o
0.94
0.94
0.94
0.96
0.94
0.96
88-95 F (31-35 C)
o
o
0.88
0.91
0.88
0.91
0.88
0.91
97-104 F (36-40 C)
NEC Table 3
Correction Factor for more than 3 Conductors in raceway or cable
Conductors
4-6
7-9
10 - 24
25 - 42 43 or more
Factor
0.80
0.70
0.70*
0.60*
0.50*
* includes effect of a load diversity of 50%
NEC Table 4
Dimensions and internal areas of Electrical Metallic Tubing (EMT) and Conduit
Sizes (inches)
Internal Ø Area m2
1 1/2
1.610
2.040
2
2.067
3.360
2 1/3
2.469
4.790
3
3.068
7.380
3 1/2
3.548
9.900
4
4.026
12.720
NEC Table 5
Dimensions of several rubber and thermoplastic-covered conductors
Types RFH-2, RH,
Types TFN, THHN,
Types TF, THW, TW
RHH
THWN
Size
AWG
Approx.
Approx.
Approx.
Approx.
Approx.
Approx.
2
2
MCM
Ø (inches) Area m
Ø (inches) Area m Ø (inches) Area m2
14
0.2040
0.0327
0.1310
0.0135
0.1050
0.0087
12
0.2210
0.0384
0.1480
0.0172
0.1220
0.0117
10
0.2420
0.0460
0.1680
0.0222
0.1530
0.0184
8
0.3280
0.8450
0.2450
0.0471
0.2180
0.0373
6
0.3970
0.1238
0.3230
0.0819
0.2570
0.0519
4
0.4520
0.1605
0.3720
0.1087
0.3280
0.0845
3
0.4810
0.1817
0.4010
0.1263
0.3560
0.0995
o
75 C
30
40
55
75
100
115
135
155
180
210
240
280
315
485
0.94
0.88
2
1
1/0
2/0
3/0
4/0
0.5130
0.5880
0.6290
0.6750
0.7270
0.7850
0.2061
0.4330
0.1473
0.2715
0.5080
0.2027
0.3107
0.5490
0.2367
0.3578
0.5958
0.2781
0.4151
0.6470
0.3288
0.4840
0.7050
0.3904
dimensions of RHH and RHW
0.3880
0.4500
0.4910
0.5370
0.5880
0.6460
0.1182
0.1590
0.1893
0.2265
0.2715
0.3278
NEC Table 6
Maximum no. of conductors in conduits or tubing for most building wire types (TW, XHHW, RHW, RHH, T
Conduit or Tubing (Inch)
AWG & MCM
1/2
3/4
1
1 1/4
1 1/2
2
2 1/2
14
9
15
25
44
60
99
142
12
7
12
19
35
47
78
111
10
5
9
15
26
36
60
85
8
2
4
7
12
17
28
40
6
1
3
5
9
13
21
30
4
1
2
4
7
9
16
22
3
1
1
3
6
8
13
19
2
1
1
3
5
7
11
16
1
1
1
3
5
8
12
1/0
1
1
3
4
7
10
2/0
1
1
2
3
6
8
3/0
1
1
1
3
5
7
4/0
1
1
2
4
6
250
1
1
1
3
4
300
1
1
1
3
4
350
1
1
1
2
3
500
1
1
1
3
3
inum
o
90 C
35
40
60
80
110
130
150
175
205
235
275
315
355
545
0.96
0.91
, THW)
3
3 1/2
4
171
131
62
47
35
29
25
18
15
13
11
9
7
6
5
5
176
84
63
47
39
33
25
21
17
14
12
10
8
7
6
108
81
60
51
43
32
27
22
18
15
12
11
9
8
CIRCUIT
BREAKER
RATING
AMPERE AMPERE
TRIP
FRAME
15
50
20
50
30
50
40
50
50
50
60
100
70
100
100
100
125
225
150
225
175
225
200
225
225
225
250
400
300
400
350
400
400
400
500
600
600
600
700
800
800
800
1000
1000
1200
1200
1600
1600
2000
2000
2500
3000
3000
3000
4000
4000
EMT/IMC
mm Ø
15
20
25
32
40
50
65
80
90
100
CONDUIT
PVC
mm Ø
20
25
32
40
50
63
75
90
110
in Ø
½"
3/4"
1"
1-¼"
1-½"
2"
2-½"
3"
3-½"
4