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

A Ground Fault Circuit Interrupter (GFCI) is designed to enhance safety by preventing electric shock hazards. Its primary function is to monitor the current flowing through the circuit and to detect any imbalances between the outgoing current and the returning current. If it senses a ground fault—meaning that the current is flowing through an unintended path to the ground, typically due to a fault in the insulation or exposure of wiring—it will quickly de-energize the circuit, usually within a fraction of a second.

This rapid disconnection is crucial in situations where moisture is present, such as in bathrooms and kitchens, because it minimizes the risk of electric shock. By interrupting the circuit when the current to ground exceeds a specific threshold, the GFCI effectively provides a protection mechanism, significantly reducing the risk of serious injury or fatality due to electric shock.

Understanding the purpose of a GFCI is essential for electricians, as it directly relates to safety standards in the installation and usage of electrical systems.