Circuit Breaker Ratings Table

120 240 volts ac breaker breaker series ratings main devices shown in shaded area centered at top.

Circuit breaker ratings table.

Maximum loading of any circuit breaker is 80 of rating for non motor loads with exceptions as noted below. Additional standard ampere ratings for fuses shall be 1 3 6 10 and 601. Two pole breakers can be either slash or straight voltage rated whereas 3 pole breakers are all straight voltage rated. 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.

For 240 volts ac branch bre akers see table 2. The use of fuses and inverse time circuit breakers with nonstandard ampere ratings shall be permitted. Table 41b2 of the wiring regulations gives the same maximum loop impedances. Circuit breaker size 2.

The standard ampere ratings for fuses and inverse time circuit breakers shall be considered as shown in table 240 6 a. While the determination of the closing and latching duty is fairly a straightforward process the calculation of the interrupting duty for medium and high voltage circuit breakers is a bit trickier. Table 2 load maximum circuit breaker size of current resistance loads heat stoves toasters water heater 125. Series rating tables table 1.

Breaker cannot be larger than ampacity of wire except for motors and a few other loads. Miniature circuit breakers which in the uk have been manufactured since 1965 to. This exceeds the breaker s 277v line to ground voltage rating. There are a few more things to consider in the calculation such as circuit breaker interrupting time and contact parting time remote and local short circuit current sources for.

1 where x 2 or 3. 4 not valid with chkd or. 3 where y 1 or 2. Respective br anch devices shown directly below.

In this you will learn ratings of circuit breaker and making breaking capacity of circuit breaker a circuit breaker may be called upon to operate under all conditions however major duties are imposed on the circuit breaker when there is a fault on the system in which it is connected every electrical equipment will have rating mentioned on it to avoid the damage of it in the same way. 2 single pole version is restricted to 15 70 a. Of the installation will determine which type of circuit breaker should be used. You must size conductors to the lowest temperature rating marking on the breaker.