In residential electrical installations, what is the purpose of a ground fault circuit interrupter (GFCI)?

A ground fault circuit interrupter (GFCI) is specifically designed to protect against electrical shock by quickly disconnecting power when it detects an imbalance in the electrical current flowing through its circuit. This situation usually occurs when there is a ground fault, such as when a person comes into contact with a live electrical part while simultaneously being in contact with ground or a grounded surface.

The GFCI monitors the current entering and leaving a circuit; if it senses that the current is not equal (indicating some of the current is leaking—potentially through a human body), it will interrupt the electrical flow within milliseconds. This fast action significantly reduces the risk of serious injury or death from electrical shock.

In contrast, the other options do not align with the primary function of a GFCI. Although regulating power supply, preventing electrical overloads, and enhancing circuit performance are necessary aspects of electrical systems, they fall outside the specific protective role that a GFCI provides against electrical shock hazards.