PSI Barbering Practice Exam

What safety device prevents the overheating of electrical wires by preventing excessive current from passing through a circuit?

1. Circuit breaker

2. Transformer

3. Fuse

4. Switch

The correct answer is: Fuse

The correct choice is a fuse, as it is designed specifically to protect electrical circuits from excessive current flow, which can cause overheating and potentially lead to fires. A fuse contains a thin wire that melts when the current exceeds a predetermined level, thus breaking the circuit and stopping the flow of electricity. This functionality is essential for maintaining safety in an electrical system, as it helps to prevent damage to appliances and reduce the risk of electrical fires. While a circuit breaker also serves a similar function—interrupting the flow of electricity when it detects an overload—fuses operate differently. A circuit breaker can be reset after an overload occurs, while a fuse must be replaced once it has blown. This operational difference is crucial in understanding their respective roles in circuit protection. A transformer, on the other hand, is used to increase or decrease voltage levels in a circuit and does not prevent overheating caused by excessive current. Similarly, a switch is merely an on/off control device that allows or interrupts the flow of electricity in a circuit without providing protective features against overload. Therefore, the fuse is the most accurate answer to the problem presented.