Question

Why is it necessary to have an earth wire installed in a power circuit,but not in a lightning circuit.

Answer 1

Hello there I hope this answer helped you :D

It is nessary to have an earth wire installed in a power circuit, but not in a lightning circuit because currents drawn through power circuit is very high while in case of lightning circuit it is low so, if there is a fault where the machine is exposed to live wire it can cause immense damage to the user in case of power circuit.

Answer 2

Answer:

Why it is necessary to have an earth wire installed in a power circuit but not in a lighting circuit? Power circuit carries high power and costly devices. If there is some unwanted power signal(noise) in the wire it can damage the device. To reduce this effect earth is necessary.