As we know the earth wire takes no current or just a small amount of leakages current, why we should use same size as live or neutral wire in a power system??
Rule of thumb is that the earth wire should be half the csa of the phase conductor. This ensures that it can carry the maximum fault current that could occur at that point for sufficient time for the protective device to operate.
Depending upon the earthing requirements by the local electrical code, the wire sizes, material and techniques would depend upon the electrical installation needs. Earthing provides a quick passage of the electrical current to ground in the event of a failure, thus providing safety to electrical circuits as well as operators. See below for more details:
Because if something goes wrong (ie. a short) the Earth wire will need to be able transmit as much electricity as the live wires. If a thinner wire was used, it would probably melt if this happened, which would remove the earth connection, and possibly burn down the house.
Normally the earth wire carries small current leakages only. However in some accidents like electric motor failurs in a refrigerator or in other big motors in the factory,higher currents may leak. Therefore, the ground wires are wired one size smaller than the normal wire used for the electrical equipment to avoid burning of wire insulation.
I have house I would like to install earth wire (sys)how can I know the size of earth wire
