What is the role of a GFCI in electrical safety?

• A. It detects ground faults quickly and interrupts the circuit to prevent shock, typically for receptacles and feeders in wet or damp areas.
• B. It regulates line voltage to prevent surges.
• C. It stores electrical energy for short periods.
• D. It measures insulation resistance.

Answer: (A)

A GFCI protects people by detecting ground faults quickly and interrupting the circuit to prevent electric shock, especially in wet or damp areas. It does this by monitoring the current flowing in the hot and returning through the neutral. If any leakage to ground occurs—such as through a person touching a live conductor and a grounded surface—the device detects an imbalance (usually about 4–6 mA) and trips within roughly 25 milliseconds, cutting off power before serious harm can occur. This protection is why GFCIs are common on receptacles in bathrooms, kitchens, outdoors, and other damp locations.

This isn’t about regulating voltage to prevent surges, storing electrical energy, or measuring insulation resistance. Those functions belong to other devices or tests, not a GFCI.