If a fuse is used for additional overcurrent protection near the shore power inlet, what must be true about its AIC?

The correct answer emphasizes that the fuse must not blow before the main shore power circuit breaker. This principle is important for ensuring that the main circuit protection remains the first line of defense against overloads and faults.

In a well-designed system, the main shore power circuit breaker is engineered to handle specific overload conditions and is sized to trip at a level that protects the wiring and equipment without nuisance trips. If the additional fuse blows before the circuit breaker, it could lead to operational interruptions and could compromise the system's intended protection strategy. The circuit breaker is designed to manage and respond to the overload conditions in a manner that will allow for safe operation of the onboard electrical systems.

Thus, while the fuse provides additional overcurrent protection, it is crucial that it functions to complement the main circuit protection rather than preempt it. The fuse should be appropriately rated to ensure it reacts in coordination with the main circuit breaker, maintaining the integrity and safety of the overall electrical system.