W-C-375-SUP-2 Circuit Breakers, Molded Case; Branch Circuit and ServiceThis specification covers the general requirements and test procedures for molded case circuit breakers which fall within the general parameters specified in table XVI which are specifically designed to provide service-entrance, feeder, meter-service, or branch circuit protection and rated at not more than 4,000 amperes and 600 volts ac, 60 hertz Hz see 3.1 and 6.1.

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W-C-375E

TABLE VIII. Group C inspection.

Examination or test 1/

Requirement paragraph

Method paragraph

Group I 2/

Overload - - - - - - - - - - - - - - - - - - - - - Tungsten lamp load 3/ - - - - - - - - - - - Temperature and 100% calibration

at 25°C - - - - - - - - - - - - - - - - - - - - Endurance - - - - - - - - - - - - - - - - - - - Short circuit - - - - - - - - - - - - - - - - - - - Dielectric withstanding voltage - - - - -

Group II 2/

200% calibration at 25°C - - - - - - - - - Short circuit interruption - - - - - - - - - -

250% calibration at 25°C - - - - - - - - - Dielectric withstanding voltage - - - - - -

Group III 2/ Special short circuit

Crossover (current limiters of

fuses) 4/ - - - - - - - - - - - - - - - - - - - Crossover (dummy fuses) - - - - - - - - Maximum IC 5/ - - - - - - - - - - - - - - -

Maximum energy - - - - - - - - - - - - - -

250% calibration at 25°C - - - - - - - - - Dielectric withstanding voltage - - - - - -

3.12

3.7

3.9

3.10

3.11

3.12

3.13

3.14

3.15

3.12

3.16

3.17

3.18

3.19

3.15

3.12

4.7.3

4.7.4

4.7.6

4.7.7

4.7.8

4.7.9.1

4.7.10

4.7.11

4.7.12

4.7.9.2

4.7.13

4.7.14

4.7.15

4.7.16

4.7.12

4.7.9.2

1/ Group I tests shall be conducted on all sample units, group II tests shall be conducted on sample units with the high fault currents of table XV. Fused type sample units shall be tested to the requirements of groups I and III.

2/ Group I tests apply to all circuit breaker designs, secondary sample group II tests apply to circuit breaker designs with high interrupting capacity ratings (see 4.5.1.1) and group III tests apply to fused circuit breakers (see 4.5.1.2).

3/ Tests made only on breakers rated at 50 amperes or less, rated 125 or

125-250 volts or less.

4/ "O" operation conducted slightly above crossover to ensure operation of current limiters or fuses. Cotton and cheesecloth indicators shall be used when crossover current is less than short circuit current.

5/ No cheesecloth or cotton indicators used in circuit breaker area.

Cotton used to cover openings in current limiter area. Test shall be conducted with one half of the current limiters in the "as received"

condition and the other half shall be conditioned at (90°C for 24 hours) then subjected to 95 ±5 percent relative humidity at 20-25°C for 5 days). Conditioned sample shall be tested no later than one hour after removal from the conditioned environment.