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

3.4.18 Ganging provisions. A single-pole circuit breaker rated at 120/240 volts ac, shall be designed to permit simultaneous operation with a similar adjacent circuit breaker, and shall have provision for the connection of the handle with that of a similar breaker.

3.5 Calibration. When circuit breakers are tested as specified in 4.7.2, the tripping times (see 6.7.1) shall not exceed the limits shown in table II for the applicable current and temperature specified (see 3.1 and table IX).

TABLE II. Calibration tripping times.

Current rating in amperes

Maximum tripping time in minutes at

200 percent rated current

Maximum tripping time in hours at 125 percent

or 135 percent rated current

0 - 30

31 - 50

51 - 100

101 - 225

226 - 400

401 - 600

601 - 800

801 - 1,000

1,001 - 1,200

1,201 - 1,600

1,601 - 2,000

Over 2,000

3.5.1 Adjustable magnetic trip calibration. When subjected to the tests specified in 4.7.2.1, automatic tripping shall occur at the highest adjustment and shall be within the range of 80-110 percent of the marked tripping current. Tripping at the lowest setting shall be no greater than the tripping current at the highest setting (unless otherwise specified, see 3.1).

3.6 Overload. When circuit breakers are tested as specified in 4.7.3, there shall be no electrical failure, evidence of mechanical damage, and the fuse used to indicate arc-over shall not be ruptured.

3.7 Tungsten filament lamp load. When tested as specified in 4.7.4, circuit breakers shall not trip automatically nor freeze in the "ON" position.

3.8 100 percent calibration at 40°C ±3°C. When tested as specified in 4.7.5, circuit breakers shall not trip automatically.

3.9 Temperature and 100 percent calibration at 25°C ±3°C. When tested as specified in 4.7.6, circuit breakers shall not trip automatically and the temperature rise at the wiring terminals or lugs shall not exceed 50°C. In addition, the temperature rise of materials used in construction shall not exceed those specified in table III. The temperature rise at the terminals and casings of limiters in fused circuit breakers shall not exceed 85°C.

3.10 Endurance. When tested as specified in 4.7.7, there shall be no electrical or mechanical failure of the device and the fuse shall not be ruptured. In addition, circuit breakers shall meet the requirements of 3.5 during the calibration check following the endurance test.

3.11 Short circuit. When tested as specified in 4.7.8, there shall be no electrical or mechanical failure of the circuit breaker and the fuse specified in 4.7.3 shall not be ruptured. The case shall not be cracked or broken, cotton or cloth indicators shall not be ignited and the insulation of the conductors used to wire the device shall show no evidence of damage. After the final operation, the circuit breaker shall have conductivity in the closed position at rated voltage. During the 200 percent rated current test, the circuit breaker shall trip automatically within the maximum time

specified in table II.