How to Design-In Product
Safety Compliance
I. Identify Requirements
II. Construction Requirements
III.Performance Testing Requirements
IV.Production Testing Requirements
Identify Requirements
• Identify the nature or scope of your product
• What market will you distribute your product (U.S.A.,
Canada, Europe, Far East, etc.)
• What certification mark will you use for compliance
• What local ordinances and standards are in place (NV
Gaming Commission & NFPA 70)
• Have the compliance specification/standard on file for
reference
Construction
• Frame & Enclosure
-
Should have the strength and rigidity
to resist the increase of electrical
shock, injury to person, or risk of fire
under normal applications
Construction
• External Material
-
External material such as steel, wood,
aluminum, glass, and composites can be
used for the enclosure.
-
If any of these materials are combustible
and have a surface area greater than 10 sq.
feet they are subject to a flame index less
than 200 when tested against the following
standards
Construction
• UL 723 (Surface Burning Characteristics of
Building Material)
• ASTM E162 (Surface Flammability of
Materials Using a Radiant Heat Energy
Source)
Construction
• Enclosure Bottom Openings
-
A barrier or pan of noncombustible material
must be used to prevent a fire hazard in the
event of flaming particles, burning insulation,
and molten metal
-
The barrier would be commonly placed
under motors, wires, switches,
transformers, etc. that upon failure
could pose a fire hazard
Blue = Minimum Barrier
Area
Red = Area of the
component
Yellow = Means of finding
minimum area of blue.
This is a 5 degree tangent
from red area
Construction
• Accessibility of Un-insulated live parts, filmcoated wire, moving parts
- If and opening in an enclosure would allow
access to un-insulated live parts, film-coated
wire, moving parts the opening has specific
dimensions.
- If < than 1 inch (articulate probe)
- If > than 1 inch (non-articulate probe)
Construction
Construction
3/4 in
Minimum Distance from
Opening to Part
4-1/2 in
1 in
6-1/2 in
1-1/4 in
7-1/2 in
1-7/8 in
15-1/2 in
2-1/8 in
17-1/2 in
Dimensions of Opening
Construction
• Supply Connections
- Can be permanent or detachable
- Must be under 15 feet in length
- Must have strain relief & bushing
- Must comply to ANSI Plug Types
Construction
Amperes, Volts
15,
20,
30,
15,
20,
30,
125
125
125
250
250
250
ANSI Designation
C73.11
C73.12
C73.45
C73.20
C73.51
C73.52
Construction
• Grounding & Bonding
- Grounding of all dead metal parts should be
available if they can become energized by a
single fault condition
- Un-insulated metal parts that are likely to
become energized and provide a shock hazard
in normal operation or service must be
bonded for grounding
Construction
- A separate bonding conductor or strap must be
used
- Be protected from damage or located within
enclosure
- Be secured by a bolt, clamp, rivet, etc. and be
able withstand a temperature of 850º F
Construction
• Protection Against Shock, Fire, Personnel Injury
-
means should be designed into the product to
protect individuals
-
the degree of protection is based on the
nature of the device, for example
1. degree of exposure
Construction
2. Sharpness of moving parts
3. Risk of unintentional contact with moving parts
4. Speed and movement of moving parts
5. Risk of fingers, hair, clothing, etc. being drawn
into moving parts.
Construction
• Components
- Attachment Plugs & Receptacles (UL 498)
- Filters, Electromagnetic Interference (UL 1283)
- Motors, Electric (1004)
- Printed-Wiring Boards (UL 796)
Construction
-
Switches, Snaps, General-use (UL 20)
-
Wires & Cables, Thermal plastic-Insulated
(UL 83)
Performance Tests
• General Power
– Device should be powered at rated voltage
and normal operating Hz
– An IR test should be conducted at 250 VDC
with a resistance > 30 kohms
Performance Tests
• Starting Current Test
-
Device should be powered on 3 times
sequentially at rated voltage and current
without tripping fuse or over-current
protection devices.
-
Device should be at room temperature for
each test and the motor can come to a
complete rest prior to the next test
Performance Test
• Leakage Current Test
-
measurement of leakage current that are
present under normal and signal fault
conditions on conductive surfaces or ground.
Performance Test
Performance Test
- Leakage Current Limits
a) .75 mA when ground closed and S1 is closed
b) 1.0 mA when ground opened and S1 is closed
c) 2.0 mA when ground opened and S1 is opened
Performance Tests
• Temperature Tests
-
when device is tested at maximum load the
temperature should not reach a point to:
-
cause risk of a fire
-
damage materials within the device
-
reach temperature in (table 33.1)
Component
Temperature in F
Motor Class 130
180º
Capacitors Electrolytic
72º
Fuses
117º
Insulated Conductors
63º
Electrical Insulation
117º
Handles & Knobs
140º
Other Surfaces
158º
Performance Test
• Dielectrical Withstand Test
-
performed on primary and secondary circuits
for 1 min. at 40-70 hz at 1 KVAC for no
breakdown
Performance
Performance Test
• Spill Test
-
any device with a horizontal service able to
hold a glass of liquid must be subjected to a
spill test
-
1 liter of water will be poured onto the
enclosure at a rate of 1L/min.
-
when the test is completed the device will be
subjected to the dielectrical withstand test
Performance Test
• Physical Stability Test
-
device should not tip over when it is tilted at
a 10 degree angle
-
a free standing device that is placed on the
floor and could be sit on or stood on should
not tip over when 180 lbf is placed on the
device
Performance Test
• Abnormal Test
- Under an abnormal test the device should not pose
a risk of fire, electrical shock, or injury to personnel
-
Unacceptable conditions include
1. flame emitted from enclosure
2. single layer of cheesecloth or tissue paper glows
3. 3 amp fuse opens
Performance Test
- Samples of abnormal tests include; operating
device with cooling fans disconnected, overload
of power supply, malfunction of components in
primary circuit (ex. Shorts), wrong voltage
selected
- Test duration is typically conducted for 1 hour
Performance Test
• Stain Relief
-
The power cord should be detached and a
35 lb weight is attached to the cord for
1 min.
Performance Test
• Grounding Impedance Test
-
The ground impedance path will be subjected to 25
amps for 1 minute with a resistance not to exceed
100 mohms.
-
The voltage should be < 12 volts AC with 60 Hz.
-
Test points are between input ground and grounded
external parts
Performance Test
Performance Test
• Impact Test
-
Three representative samples of the device
must withstand an impact test without any
signs of cracks or openings after impact
-
A steel sphere weighing 1.18 lbs will be
dropped 51 inches or swung from a
pendulum at 51 inches
Manufacturing Test
• Production Dielectrical Withstand Test
– Each appliance will be subjected to the
dielectrial withstand test without breakdown
– Appliance must be fully assembled
Manufacturing Test
• Production Grounding-Continuity Test
-
Every product that will be supplied with a power
cord that is grounded will be subjected to a
continuity test
-
the test is between input ground and chassis ground
-
instrument used could be an ohmmeter,
battery/buzzer device, or similar devices