What distinguishes a fuse from a circuit breaker?

The essence of the distinction between a fuse and a circuit breaker lies in their operation under overcurrent conditions. A fuse is designed to protect electrical circuits by melting its internal wire or element when the current exceeds a specified limit, thereby interrupting the flow of electricity. This permanent action means that once a fuse has melted, it must be replaced to restore the circuit, showcasing its nature as a one-time use device.

In contrast, a circuit breaker serves the same protective role but can be reset after tripping. It utilizes mechanical or electronic means to interrupt the current flow and can be manually or automatically reset once the fault condition has been cleared, allowing for continued use without the need for replacement.

This fundamental operational difference underlines why the response about a fuse melting at overcurrent and a circuit breaker being reset correctly highlights the distinct purposes and functionalities of these protective components in electrical systems.