A fuse is a type of low resistance resistor that acts as a sacrificial device to provide over current protection, of either the load or source circuit. Low resistance causes the fuse wire to melt if a current more than the safe current for the appliance starts flowing through the circuit. Besides, the wire of fuse has very low melting point. When high current flows through the circuit due to overloading or a short circuit, the wires gets heated and melts. As a result, the circuit is broken and current stops flowing.