What causes the metal strip in an electrical fuse to melt?

The metal strip in an electrical fuse melts primarily due to high amperage demands. Fuses are designed to protect electrical circuits by breaking the circuit when the current exceeds a specified safe level. When there is a surge in current—often due to excessive electrical load or a fault in the circuit, such as a short circuit—the current flowing through the fuse increases significantly. This increase in amperage causes the metal strip to generate heat, as it encounters resistance to the flow of electrical current. Once the temperature rises to a point where it exceeds the melting point of the metal, the strip melts, breaking the circuit and preventing further damage to the electrical system or potential fire hazards.

This function is critical for maintaining safety and integrity in electrical systems, as it ensures that excessive current does not lead to overheating or other dangerous situations.