What is the function of a Ground Fault Circuit Interrupter (GFCI)?

A Ground Fault Circuit Interrupter (GFCI) is a crucial component designed to enhance safety in electrical systems primarily by preventing electrical shock. Its primary function is to monitor the current flowing through the circuit; if it detects an imbalance between the outgoing and incoming current, it means that electricity is leaking to the ground (which can happen if a person comes into contact with a live wire). Upon detecting this imbalance, the GFCI quickly interrupts the power supply, thereby protecting individuals from potentially fatal electric shocks.

The design of a GFCI makes it particularly effective in areas where moisture is present, such as kitchens and bathrooms, where the risk of electric shock is significantly higher. The GFCI's ability to react swiftly—often in milliseconds—makes it a vital safety device in household and commercial electrical systems.

Other options such as increasing circuit capacity, providing surge protection, or measuring current flow do not accurately describe the primary role of a GFCI. While surge protectors are aimed at preventing damage from voltage spikes, and current measuring devices serve a different function entirely, the GFCI's focus on shock prevention is what distinguishes it as a critical safety mechanism in electrical installations.