A 120-volt circuit supplies 38 amperes of continuous load. What is the minimum standard size fuse required for overcurrent protection of the circuit?

To determine the minimum standard size fuse required for overcurrent protection in a circuit, you need to consider the current load and the appropriate sizing rules for fuses. In this case, the circuit has a continuous load of 38 amperes.

According to the National Electrical Code (NEC), fuses and circuit breakers should generally be rated at 125% of the continuous load to ensure proper overcurrent protection. Therefore, the calculation for the fuse size would be:

1. Calculate 125% of the continuous load:

• 38 amperes x 1.25 = 47.5 amperes.

2. Since fuses come in standard sizes, you need to choose the next size up from 47.5 amperes to ensure proper protection. The standard sizes available typically include 30 A, 40 A, 50 A, and 60 A.

Choosing 50 amperes is the closest option above 47.5 amperes and is typically adequate for protecting circuits against overcurrent without tripping under normal operating conditions. This ensures that the circuit can handle the load safely while providing effective overcurrent protection.

Choosing any fuse rated lower than 50 amperes would not comply with the NEC guidelines for continuous loads, as it