An electric fuse works on the following principle:

An electric fuse works on the heating effect of electric current.

When excessive current flows through the circuit:

Heat produced in the fuse wire increases.
The fuse wire melts due to its low melting point.
The circuit breaks automatically.
Electrical appliances are protected from damage.

This principle is based on Joule's Law of Heating:

where:

H = Heat produced
I = Current
R = Resistance
t = Time

Therefore, an electric fuse works on the heating effect of current.