In low-voltage distribution system, fuse is a kind of electrical appliance that plays a role of safety protection. Fuse is widely used in power grid protection and electrical equipment protection. When short-circuit fault or overload occurs to power grid or electrical equipment, it can automatically cut off the circuit to avoid damage to electrical equipment and prevent accident spreading.

The fuse is composed of insulating base (or support), contact, melt, etc. the melt is the main working part of the fuse. The melt is equivalent to a special wire connected in series in the circuit. When the circuit is short circuited or overloaded, the current is too large, and the melt melts due to overheating, thus cutting off the circuit. The melt is often made into filaments, grids or flakes. The melt material has the characteristics of low relative melting point, stable characteristics and easy fusing. Lead tin alloy, silver plated copper sheet, zinc, silver and other metals are generally used. In order to safely and effectively extinguish the arc, the melt is generally installed in the fuse housing and measures are taken to extinguish the arc quickly.

Fuse has the advantages of simple structure, convenient use and low price. It is widely used in low-voltage system.