Question

what is earthing? why is it necessary to earth metallic electric appliances

Answer 1

We know that the earth is the source and sink of charge. Earthing is done to make the unwanted charges flow down to earth through a conducting wire.

Earthing is the proper connection of exposed metal parts of an electrical circuit to the ground. It is accomplished by thick copper wires. Earthing protects the appliances and human beings in case of insulation fail or accidental short circuit. When the live wire touches the earth wire, large current flows through it and causes the fuse to blow off or circuit breaker to trip and thereby protecting the appliance as well as users.