Current Circuit Breaker Ampere Ratings Table

Circuit breaker selection for cbp duty.

Current circuit breaker ampere ratings table. In short we must use the proper size of circuit breaker according to the device i e. Breakers should be sized at 125 for a continuous load and 100 for a non continuous load which comes out the same when you. Table a 208 volt ac input protection devices see page 7 for notes drive catalog number frame hp rating pwm freq. Every circuit breaker has a specified amperage amount of current.

In iz 0 25 x iz in ampere rating iz load ampere. 1 ampere rating in 2 short circuit breaking capacity if 3 application type. We want install 1 unit single phase motor full load ampere is 20 ampere. If we use a 100a circuit breaker for 30a circuit it wont protect the circuit from fault currents and may burn and damage the device as more than 30 amperes current won t trip the circuit breaker.

It s fine to exceed this for short periods of time but continuous current above this amount could cause enough heat to trip the breaker. A recommended choice for the three outgoing circuits 1 2 and 3 would be current limiting circuit breakers types nsx400 l nsx250 l and nsx100 l. The standard for most household circuits are rated either 15 amps or 20 amps. These conditions per ul 489 underwriters laboratories standard for safety for molded case circuit breakers and circuit breaker enclosures include mounting the cb in free air i e.

1 ampere rating in formula. Multiply the amperage by 0 8. Power supply 240vac 50 hz. This rating is labeled on the breaker itself.

For everyday use it s a good idea to expose the breaker to a maximum of 80 of the rated amperage. Breaking capacity icu required for these circuit breakers is given in the figure h46 as 56 ka. Input ratings output amps dual element time delay fuse non time circuit breaker 3 motor circuit protector 4 140m motor starter with adjustable current range 5 6 nd hd khz c amps kva cont. Cb current should not be lower nor highest but 125 of circuit s current.

The icu rating in each case 150 ka. An important note to remember is that circuit breakers can only handle about 80 of their overall amperage.