Fuse wire is basically used to prevent excessive current to enter electric circuits connected with valuable devices. This is done to prevent damage to all the electrical devices.
For the fuse wire concept to work, it should have high resistance and a low melting point. Due to high resistance, it would generate more heat and due to low melting point, it would melt and break the circuit during excess electric supply.
Thus keeping these properties in mind, tin and lead were selected due to a match with requirements.
So, fuse wire is made up of an alloy of tin and lead.