which substance is used for making a fuse wire? Can copper be used? If yes, it should be a thin wire or thick.

Fuse (from the Latin "fusus" meaning to melt) is a type of sacrificial overcurrent protection device. Its essential component is a metal wire or strip that melts when too much current flows, which interrupts the circuit in which it is connected. A fuse is a thin wire made of a material like tin or tin-lead alloy having low melting point which melts and breaks off the circuit if the current exceeds the safety limit.

 

A copper wire can not be used as a fuse wire because it has a high melting point. It will not melt easily when a high electric current passes through it and may prove harmful to the appliances attached to it and the user of the appliances