What is the primary difference between fuses and circuit breakers?

The primary difference between fuses and circuit breakers lies in their operational design and functionality, particularly regarding their one-time use. A fuse is designed to provide overcurrent protection by melting its internal element when the current exceeds a specified level for a certain duration. This action permanently disconnects the circuit; thus, once a fuse blows, it has to be replaced as it cannot be reused.

In contrast, a circuit breaker serves the same protective purpose but does so by utilizing a mechanical switch that interrupts the flow of electricity in the event of an overload or short circuit. After a circuit breaker trips, it can be reset by flipping a switch back to its original position, allowing for multiple uses without the need for replacement.

The notion that a fuse can only be used once is crucial to understanding its functionality, as it highlights the need for regular maintenance and replacement in systems using fuses, unlike those using circuit breakers where the maintenance tends to be less frequent.