Which device is resettable after a fault, unlike a fuse?

• A. Circuit breaker
• B. Fuse
• C. Surge protector
• D. Motor starter

Answer: (A)

A device that can be reset after a fault is a protective device designed to open the circuit when current is excessive and then be reset to restore power once the issue is fixed. A circuit breaker does exactly that: it trips to interrupt the circuit when overcurrent is detected and can be reset after the fault is cleared, re-energizing the circuit without needing a new part. A fuse works differently; its metal link melts under overload, creating a permanent open circuit that requires replacing the fuse. Motor starters and surge protectors have important protective or control roles, but the clear behavior the question is testing is that circuit breakers are resettable after tripping.