What condition would cause a Ground Fault Circuit Interrupter (GFCI) to trip?

A Ground Fault Circuit Interrupter (GFCI) is designed to protect individuals from electric shock by monitoring the current flowing through the circuit. It trips or cuts off power when it detects an imbalance between the outgoing and incoming current. Specifically, this situation occurs if a supply lead comes into contact with a grounded surface, causing some of the current to flow through an unintended path (potentially through a person to the ground). This imbalance indicates a fault condition, prompting the GFCI to trip in order to ensure safety.

This is why the condition where a supply lead is shorted to ground directly triggers the GFCI. It is a crucial safety feature that helps prevent serious electrical shocks or fires caused by ground faults. Other conditions, such as circuit overloads or power surges, are managed by different protective devices, like circuit breakers or fuses, rather than GFCIs. Water entering a circuit could also create hazards, but it doesn't specifically cause a GFCI to trip unless it results in a ground fault condition.