How does a circuit breaker differ from a fuse?

How does a circuit breaker differ from a fuse?

• A. A fuse is resettable; a breaker is sacrificial.
• B. A breaker is resettable; a fuse is sacrificial.
• C. Both are resettable.
• D. They are identical in operation.

Answer: (B)

The key idea is whether the protective device can be reused after it trips. A fuse contains a thin metal link that melts when overcurrent occurs, opening the circuit permanently until you replace the fuse. A circuit breaker interrupts current by tripping a mechanism and opening the contacts, and after the fault is cleared you can reset it by flipping the breaker back on. That makes the breaker resettable and the fuse sacrificial. The other statements either imply one is reusable when it isn’t, or treat both as the same, which isn’t accurate.

The key idea is whether the protective device can be reused after it trips. A fuse contains a thin metal link that melts when overcurrent occurs, opening the circuit permanently until you replace the fuse. A circuit breaker interrupts current by tripping a mechanism and opening the contacts, and after the fault is cleared you can reset it by flipping the breaker back on. That makes the breaker resettable and the fuse sacrificial. The other statements either imply one is reusable when it isn’t, or treat both as the same, which isn’t accurate.