For that 34-ampere three-phase squirrel-cage motor, what is the maximum inverse-time circuit breaker permitted for branch-circuit short-circuit and ground-fault protection, using the next standard size allowance?

Giải thích

An inverse-time breaker is permitted at 250 percent of full-load current: 34 x 2.50 = 85 A, which is not a standard rating, so the next higher standard size of 90 amperes may be used. The 100-ampere answer skips a standard size, and 70 amperes corresponds to the 175 percent dual-element fuse calculation instead.