Which protective device can be reset after tripping, rather than replaced, and is used to interrupt excess current?

• A. Circuit breaker
• B. Fuse
• C. Thermal overload
• D. Pushbutton

Answer: (A)

A circuit breaker is a protective device that senses excess current and interrupts the circuit when it trips. After tripping, it can be reset by turning the breaker off and then back on (or using a reset action), restoring service without replacing any components. This resettable nature is what distinguishes it from other protective devices. Fuses, on the other hand, contain a metal link that melts when overcurrent flows; once it blows, the fuse must be replaced. A thermal overload protects equipment like motors by tripping on overheating, and some designs allow reset after cooling, but in common panel protection, the resettable breaker is the standard device used to interrupt and then restore current. A pushbutton is simply a control, not a protective device that automatically interrupts excess current.