Explain the importance of using in a household electric circuit (i) fuse, and (ii) earthing wire.

(i) Fuse
A fuse is a short-length wire of low melting point, which is considered to be one of the important devices, used to protect the household electrical system from getting damaged due to either overload or short circuit.

A fuse wire is a short-length safety wire made up of tin-plated copper because it has a low melting point. If the current exceeds a safe value, the wire melts and breaks the circuit or discontinue the flow of current, so that our household electrical equipment remains safe.  

(ii) Earthing wire
Earthing wire is a safety wire, generally coated with green insulation, connects the metal parts of appliances to the earth. It is made up of thick copper wires. Its function is to conduct the excess current to the earth, in case of insulation failure or accidental short circuit, so that the risk of accidents such as fatal electric shock will be reduced.


To avoid the risk of the electric shock, the metal body of an electrical appliance is 'earthed' or 'grounded'. Earthing means connecting the metal case (or metal body) of an electrical appliance to the earth (at zero potential) through a metal wire called 'Earth Wire'.

The electric wiring in houses, shops, or factories has three wires: liveneutral and earth. The first two carry electric current from the power station and the third is earthed by connecting it to the earth through a metal wire called 'Earth Wire'.
Metallic bodies of electric appliances such as refrigerator, electric irons, televisions are connected to the earth wire so that when any fault occurs or the live wire touches the metallic body the charge flows to the earth without damaging the appliance and without causing any injury to the humans.


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