Which protective device protects against overcurrent by melting its fuse element?

Which protective device protects against overcurrent by melting its fuse element?

• A. Fuses
• B. Circuit Breakers
• C. GFCIs
• D. Surge Protectors

Answer: (A)

Overcurrent protection relies on a device that stops the current when it becomes too high. A fuse does this by using a thin metal link that heats up as current increases. When the current exceeds the fuse’s rating, the element melts and opens the circuit, permanently interrupting the path to prevent damage. After that happens, the fuse must be replaced. This differs from a circuit breaker, which also protects against overcurrent but opens the circuit by tripping a switch and can be reset. GFCIs detect ground faults by sensing an imbalance between hot and neutral and trip to prevent shock, not for continuous overcurrent protection. Surge protectors guard against voltage spikes, diverting excess voltage to protect equipment rather than interrupting sustained overcurrent.

Overcurrent protection relies on a device that stops the current when it becomes too high. A fuse does this by using a thin metal link that heats up as current increases. When the current exceeds the fuse’s rating, the element melts and opens the circuit, permanently interrupting the path to prevent damage. After that happens, the fuse must be replaced.

This differs from a circuit breaker, which also protects against overcurrent but opens the circuit by tripping a switch and can be reset. GFCIs detect ground faults by sensing an imbalance between hot and neutral and trip to prevent shock, not for continuous overcurrent protection. Surge protectors guard against voltage spikes, diverting excess voltage to protect equipment rather than interrupting sustained overcurrent.