Which device senses current imbalance and interrupts the circuit to protect people from shock?

Which device senses current imbalance and interrupts the circuit to protect people from shock?

• A. A surge protector trips on ground fault.
• B. A fault current causes the main breaker to trip.
• C. Ground-fault circuit interrupter senses current imbalance and interrupts.
• D. A fuse is used for GFCI.

Answer: (C)

The device that protects people from shock by sensing a current imbalance and interrupting the circuit is the ground-fault circuit interrupter. It continuously monitors the current in the live and neutral conductors; under normal conditions these currents are equal. If some current leaks to ground—such as through a person—the current in the hot and neutral no longer matches. The GFCI detects this small difference, typically a few milliamps, and rapidly opens the circuit to stop the hazardous current flow, minimizing the risk of electric shock. Surge protectors are designed to limit voltage spikes and do not rely on current balance to protect against shock. The main breaker trips on overcurrent or short circuits, not on leakage to ground, so it’s not tuned for rapid protection from shock due to leakage. A fuse is a general overcurrent device and is not what a GFCI uses to detect and interrupt leakage; GFCIs are designed specifically to detect imbalance and trip quickly in response to ground faults.

The device that protects people from shock by sensing a current imbalance and interrupting the circuit is the ground-fault circuit interrupter. It continuously monitors the current in the live and neutral conductors; under normal conditions these currents are equal. If some current leaks to ground—such as through a person—the current in the hot and neutral no longer matches. The GFCI detects this small difference, typically a few milliamps, and rapidly opens the circuit to stop the hazardous current flow, minimizing the risk of electric shock.

Surge protectors are designed to limit voltage spikes and do not rely on current balance to protect against shock. The main breaker trips on overcurrent or short circuits, not on leakage to ground, so it’s not tuned for rapid protection from shock due to leakage. A fuse is a general overcurrent device and is not what a GFCI uses to detect and interrupt leakage; GFCIs are designed specifically to detect imbalance and trip quickly in response to ground faults.