Question

Describe with the aid of a diagram some form of a fuse which is used in the electric lighting circuit of a house. Give two reasons why a fuse must not be replaced by an ordinary copper wire.

Answer 1

The figure above shows the most common fuse arrangement in which the fuse wire is stretched between the two metallic terminals T₁ and T₂ in a porcelain holder. This holder fits into a porcelain socket having two metallic terminals, to each of which the live wire of the circuit is connected. A fuse must not be replaced with a copper wire because copper has very low resistivity and a high melting point.

Ordinary wire has low resistance and high M.P. and when High current passes into the appliance and gets damaged even then fuse will not melt and will not disconnect the appliance.