Question

What is the role of fuse, used in series with any electrical appliance? Why should a fuse with defined rating not be replaced by one with a larger rating?

Answer 1

A fuse in a circuit prevents damage to the appliances and the circuit due to overloading. The use of an electric fuse prevents the electric circuit and the appliance from a possible damage by stopping the flow of unduly high electric current. The Joule heating that takes place in the fuse melts it to break the electric circuit. If a fuse with a defined rating replaced by one with a larger rating, then the joule heating fails to melt the fuse and hence, the circuit is not broken. This results in burning of the appliance.