Define the purpose of a Ground Fault Circuit Interrupter (GFCI).

Define the purpose of a Ground Fault Circuit Interrupter (GFCI).

• A. To detect overcurrent and protect wiring from overheating
• B. To regulate voltage in branch circuits
• C. To detect imbalance between live and neutral currents and quickly interrupt power to prevent shock
• D. To monitor power factor and compensate

Answer: (C)

A GFCI is designed to protect people from electric shock by sensing any leakage of current to ground and quickly cutting power. It does this by continuously comparing the current flowing in the live conductor with the current returning through the neutral; under normal operation they are equal. If some current escapes to ground—such as through a person touching a live part—the two currents become imbalanced, and the device trips in a few milliseconds to interrupt power. This keeps a potentially dangerous fault from delivering a sustained shock. The leakage threshold is very small (a few milliamps), which is far below where harm could occur. It’s not intended to protect wiring from overheating (that’s overcurrent protection), nor does it regulate voltage or monitor power factor.

A GFCI is designed to protect people from electric shock by sensing any leakage of current to ground and quickly cutting power. It does this by continuously comparing the current flowing in the live conductor with the current returning through the neutral; under normal operation they are equal. If some current escapes to ground—such as through a person touching a live part—the two currents become imbalanced, and the device trips in a few milliseconds to interrupt power. This keeps a potentially dangerous fault from delivering a sustained shock. The leakage threshold is very small (a few milliamps), which is far below where harm could occur. It’s not intended to protect wiring from overheating (that’s overcurrent protection), nor does it regulate voltage or monitor power factor.