[Actual] Purpose and Function of Earth Wire

The actual function of Earth Wire in an electrical transmission and distribution system is to provide a path to flow current during overvoltage faults and remove surge voltage. The main purpose of Earth Wire in an electrical transmission and distribution line is to protect the live wires from the lightning. There are many important functions and purposes of Earth Wirewhich are explained in detail. So read the full article to know the Earth Wire Function and Earth Wire Purpose in the electrical system.

The function of Earth Wire

The earth wire is used in different places for different purposes. So we are going to know the function of Earth wire in different places. The earth wire provides a path with very low resistance for fault currents to flow. When a fault occurs, such as a live wire accidentally coming into contact with a conductive part or a breakdown in insulation, fault currents need a low resistance path to return to the electrical supply source. The earth wire, connected to the grounding system, offers a direct and safe route for these fault currents to flow, allowing protective devices, such as circuit breakers or fuses, to quickly detect the fault and interrupt the circuit.

The function of Earth Wire in Domestic Circuit

In our domestic circuit, three wires are used, a phase wire, a  neutral wire, and an earth wire. Generally, the green color is used for earth wire. This earth wire is connected to the metallic body of the electrical appliances. That earth wire is also connected to the upper pin of the five pins or three-pin socket. The earth wire is mainly used in the domestic circuit for protection purposes. It protects the human from electrical shock.

The Function of Earth Wire in Transmission Line

In the Overhead Transmission line, Earth wire or ground wire is used. The topmost wire in an overhead transmission line is the earth wire. The topmost earth wire in the transmission line is not connected to any equipment or supply. In normal conditions, the earth wire does not carry any current. The main function of Earth wire in the transmission line is, it protects the other live conductor from lightning.

As it is the topmost wire so when lightning occurs, a large amount of voltage due to lightning is produced on the topmost earth wire. As the earth wire is connected to the ground, it discharges the overvoltage to the ground. So the lightning stroke cannot hit the other wires or conductors. Thus the other wires in the transmission line are safe from lightning.

The Function of Earth Wire in Electrical Instruments

The main function of Earth wire in electrical instruments, devices, and equipment is to provide protection against electrical shock. Generally, the earth wire is connected with the metallic noncurrent-carrying parts of electrical devices. It helps to provide a path to flow the current when the line or phase conductor touches the noncurrent-carrying parts of the electrical device.

Purpose of Earth Wire

In short, the main purposes of earth wire are,

1.      It provides a path for discharging the surge voltage.

2.      It helps to provide protection against overvoltage.

3.      It provides a path for discharging the huge amount of electrons due to lightning to the ground.

4.      It provides protection against electrical shock.

5.      It helps to detect faults in phase or neutral conductors.

6.      It can be used as a neutral conductor when neutral gets fault.

Difference between Normal Power Supply Wire and Earth Wire

(1) The power supply wire is covered with a protective layer called insulation. It keeps the electrical current inside the wire and prevents contact with other materials. This insulation helps avoid electric shocks and short circuits. On the other hand, the earth wire doesn't have insulation all the way. It is generally left bare or partially exposed. The purpose is to allow fault currents to flow safely into the ground.

(2) The power supply wire is usually bigger in size because it carries the electrical energy that powers our devices. Its size is determined based on factors like the amount of current it needs to handle and the distance it has to travel. On the other hand, the earth wire is smaller in size compared to the power supply wire. It is designed to carry fault currents, which are abnormal currents that occur during faults or accidents in the electrical system.

Read Also:

• [Main] Function and Purpose of Neutral Wire in Electrical Circuit
• The main important difference between AC and DC-Full explanation
• Why we use 220V, 50Hz AC at home instead of DC or other voltage? Full Explanation.
• Which is more dangerous AC or DC? Explained in Detail
• Why Neutral Wire is not used in Transmission Line?

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