Earthing


To connect the metallic Parts of an Electric appliance or installations to the earth to discharge the current to ground is called Earthing or Grounding.

Also, to connect the metallic parts of electric machinery and devices to the earth plate or earth electrode (which is buried in the moisture earth) through a thick conductor wire (which has very low resistance) for safety purpose is known as Earthing or grounding.

The potential of earth is 0 volt.

To earth or earthing, means to connect the part of electrical apparatus such as metallic covering of metals, earth terminal of socket cables, stay wires that do not carry current to the earth.

Importance of earthing

●      To protect human lives as well as provide safety to electrical devices and appliances from leakage current.
●      To serve as a return conductor in electric traction system and communication.
●      To avoid the risk of fire in electrical systems.
●      To Protect Electric system such as transformer etc and buildings form lighting.
●      To keep voltage as constant in the healthy phase (If fault occurs on any one phase).

Earth Wire or earth continuity conductor

That part of the earthing system which interconnects the overall metallic parts of electrical installation e.g. conduit, ducts, boxes, metallic shells of the switches, distribution boards, to ground is called earth wire.

The resistance of the earth continuity conductor is very low. According to IEEE rules, resistance between consumer earth terminal and earth Continuity conductor (at the end) should not be increased than 1Ω. In simple words, resistance of earth wire should be less than 1Ω.

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