A fuse or circuit breaker should be installed on the side of the circuit that has:

The installation of a fuse or circuit breaker is essential for protecting electrical circuits from overloads or short circuits. The correct answer refers to the importance of installing the protection device on the "hot" side of the circuit, which is typically represented by the black wire in standard wiring practices.

The black wire is used as the "live" or "hot" wire, carrying current from the power source to the devices. By placing the fuse or circuit breaker on this side, it ensures that in the event of a fault, the circuit protection device can interrupt the flow of electricity effectively, thereby providing safety for the wiring and any connected devices.

In contrast, the green wire is designated as a ground wire, and the white wire is typically used as the neutral wire, which completes the circuit back to the power source. Installing a fuse or breaker on these wires would not protect against overcurrent conditions correctly, as they do not carry the current intended for load operation in the same way the black wire does. Therefore, it is critical that the protection device is on the hot side to ensure proper operation and safety of the electrical system.