Q. What is the proper size overload, and branch-circuit, short-circuit, ground-fault protective device permitted for a hermetic compressor with a nameplate rated-load of 38A, and a branch-circuit selection current of 40A? The fusible disconnect is going to serve as the disconnecting means, the overload protective device, and the branch-circuit, short-circuit, ground-fault protective device. A) 47.5A
Explanation: As per 440.52(A)(3) of the 2005 NEC, you must use a multiplier of 1.25 (125%) for this calculation.
40 x 125% = 50A
A check of 240.6 reveals that 50A is a standard size ampere rating for fuses and inverse time circuit breakers.
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