What is the purpose of a GFCI?

• A. Detects ground faults and quickly disconnects power to prevent shock.
• B. Detects short circuits and trips the circuit breaker.
• C. Regulates voltage to protect devices.
• D. Tests insulation resistance.

Answer: (A)

Ground-fault circuit interrupters are designed to protect people from electric shock by detecting when current leaks from a live conductor to ground. They constantly monitor the current in the hot and the return path; if there’s an imbalance — meaning some current is escaping through an unintended path like a person — the device trips and cuts power in a fraction of a second. This rapid disconnection reduces the risk of serious shock, especially in wet or damp locations where contact with energized surfaces is more likely. GFCIs are commonly used in outlets in bathrooms, kitchens, outdoors, garages, and other areas where moisture is present. They don’t protect against short circuits in the wiring, don’t regulate voltage to devices, and aren’t used to test insulation resistance.