American Home Inspectors Training (AHIT) Practice Test

A main disconnect with two 60 amp fuses indicates what amperage rating?

1. 30 amps

2. 60 amps

3. 120 amps

4. 240 amps

The correct answer is: 60 amps

When determining the amperage rating indicated by a main disconnect with two 60 amp fuses, it's important to understand the concept of how fuses function in a circuit. Each fuse is capable of handling a maximum load of 60 amps. When these fuses are connected in parallel, the total potential amperage that can be supported by the disconnect is the sum of the ratings of both fuses. In this case, the two 60 amp fuses don't add up to create a higher single amperage rating since they are intended to protect different legs of a split-phase system. Instead, the circuit is typically rated based on the fuse's maximum capacity per leg, maintaining the rating of the smaller fuse if they are in a parallel arrangement. Hence, the disconnect can handle a maximum of 60 amps per each leg. This results in the understanding that while both fuses are there, they primarily protect the circuit and do not increase the amperage rating beyond the rating of the individual fuses. Therefore, it is accurate to state that the main disconnect with these two 60 amp fuses indicates an amperage rating of 60 amps.