Question

What happens if we use a fuse made up of wire which is used to make the electric circuit?

Answer 1

fuse become useless
it work as a simple wire only

Answer 2

Fuse is a safety device used to prevent from overloading in electrical circuits.
Generally fuse wire is made up of tin and lead alloy and have high resistance and low melting point.
when excess current flows, fuse wire melts and electrical circuit breaks thus prevents from overloading.
if copper wire is used as fuse then as it has high melting point , when excess current flows in circuit then fuse wire may not melt thus all the electrical appliances gets damaged.