Which device is used to quickly shut off power in a circuit when a ground fault is detected?

Which device is used to quickly shut off power in a circuit when a ground fault is detected?

• A. Fuses
• B. Circuit breakers
• C. Ground-fault circuit interrupters (GFCI)
• D. Arc-fault circuit interrupters (AFCI)

Answer: (C)

Ground-fault protection protects people by sensing leakage current to ground and instantly cutting power. This is done by a ground-fault circuit interrupter, which compares the current in the hot and neutral conductors. When the currents don’t match, indicating current is flowing somewhere else (like through a person to ground), it trips within milliseconds to stop the shock. Fuses and circuit breakers respond to overcurrent or short circuits, not specifically to ground leakage, so they may not react as quickly to a ground fault. Arc-fault interrupters focus on detecting arcing faults to prevent fires, not on stopping ground leakage. Ground-fault protection is why these devices are used in wet or damp locations to reduce shock risk.

Ground-fault protection protects people by sensing leakage current to ground and instantly cutting power. This is done by a ground-fault circuit interrupter, which compares the current in the hot and neutral conductors. When the currents don’t match, indicating current is flowing somewhere else (like through a person to ground), it trips within milliseconds to stop the shock. Fuses and circuit breakers respond to overcurrent or short circuits, not specifically to ground leakage, so they may not react as quickly to a ground fault. Arc-fault interrupters focus on detecting arcing faults to prevent fires, not on stopping ground leakage. Ground-fault protection is why these devices are used in wet or damp locations to reduce shock risk.