Why is a circuit breaker used instead of a fuse in some circuits?

• A. Circuit breakers are cheaper.
• B. Circuit breakers can be reset after tripping; fuses must be replaced after blowing.
• C. Fuses are always safer.
• D. Circuit breakers respond faster than fuses.

Answer: (B)

The main idea being tested is the practical advantage of a resettable protection device. A circuit breaker can be reset after it trips, so once the fault is fixed you can restore power quickly by switching it back on. A fuse, on the other hand, melts its conductor and breaks the circuit permanently until you replace the fuse. That means downtime and the need to get a new component after every fault.

This is why circuit breakers are preferred in many circuits: they offer quick restoration and reuse without needing replacement, which is especially handy for everyday electrical systems where faults may occur and be resolved repeatedly. The protection mechanism is similar—both respond to overcurrent to prevent damage—but the resettable nature of a breaker is the key benefit.

The other statements aren’t as reliable: cost can vary, speed isn’t universally faster for breakers, and saying fuses are always safer isn’t accurate, since safety depends on proper ratings and correct use.