Electrician's Licensing Practice Exam

What is typically resettable and acts similarly to a fuse?

1. Circuit breaker

2. Fuse box

3. Transformer

4. Relay

The correct answer is: Circuit breaker

A circuit breaker is correctly identified as a device that is typically resettable and functions similarly to a fuse. Circuit breakers are designed to automatically interrupt the flow of electricity in a circuit when they detect an overload or short circuit condition, thereby preventing damage to the electrical system and enhancing safety. Unlike fuses, which must be replaced once they blow due to an overload, circuit breakers can simply be reset after the fault has been cleared, allowing for quick restoration of service without needing replacement parts. In contrast, a fuse box is simply a housing that contains fuses to protect the circuits; it is not resettable itself since the individual fuses must be replaced when burned out. A transformer is an electrical device used to increase or decrease voltage levels and does not serve the function of protecting circuits from overloads. A relay is an electromechanical switch used to control a circuit by a low-power signal but does not perform the overcurrent protection function like a fuse or circuit breaker.