In an electrical installation or an electricity supply system an earthing system or grounding system connects specific parts of that installation with the Earth's conductive surface for safety and functional purposes. In other words, to connect the metallic parts of electric machinery and devices to the earth plate or earth electrode through a thick conductor wire for safety purpose is known as Earthing or grounding.
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We must know the suitable earthing types to ensure your system is fully protected and safety. we explains detail about all of five types earthing system types below. I hope it can help to understand about earthing system.
This system normally used for consumer power supply. No earthing system provided by power distributor. The owner must install the earthing protection by their own connection to the earth. They must installing a suitable electrode and safe arrangement for which they are responsibility to their installation.
The neutral and earthing conductor must be separately through the installation because power distributor only provide the supply neutral or protective conductor for the connection to consumer.
This system is similar with TT system but totally different in earthing supply. The distributor system not have any connections to earth or it have only a high impedance connection. It mean the usual protection is not effective for this system. This type is not for consumer power supply. It special for power distributor such as substation or generator area.
This system has the neutral of power supply with connection of earth only at one point to the source. the consumer’s earthing terminal is usually connected to the metallic Armour of the distributor’s cable into the High voltage and low Voltage transformer.
This system has the supply neutral conductor of a distribution main connected with earth at source as protective multiple earthing. The supply distributor neutral conductor is also used to return earth fault currents from the consumer installation back to the source with a safely manner.
The power supply distributor will provide a consumer’s earthing terminal which is linked to the incoming neutral conductor. This combined earth and neutral system called the protective and neutral conductor or the combined neutral and earth conductor.
The power supply distributor will provide a consumer’s earthing terminal which is linked to the incoming neutral conductor. This combined earth and neutral system called the protective and neutral conductor or the combined neutral and earth conductor.
This system is not familiar or unusual for earthing system. It a combined neutral conductor fulfills the functions of both a PE and an N conductor. The neutral conductor is the sheath of a cable and therefore is concentric with (totally surrounds) the phase conductor.
Earthing can be done in many ways. The various methods employed in earthing, (in house wiring or factory and other connected electrical equipment and machines) are discussed as follows.
Now we will brief Methods of Earthing
In plate earthing system, a plate made up of either copper with dimensions 60cm * 60cm * 3.18mm or galvanized iron of dimensions 60cm * 60cm * 6.35 mm is buried vertical in the earth pit, which should not be less than 3meter from the ground level.
A galvanized steel and a perforated pipe of approved length and diameter is placed vertically in a wet soil in this kind of system of earthing. It is the most common system of earthing.
In this method of earthing, the waterman (Galvanized GI) pipes are used for earthing purpose. Make sure to check the resistance of GI pipes and use earthing clamps to minimize the resistance for proper earthing connection.
In this method of earthing, strip electrodes of cross-section not less than 25mm * 1.6mm is buried in a horizontal trenches of a minimum depth of 0.5meter. If copper with a cross-section of 25mm * 4mm is used and a dimension of 3.0mm. if it’s a galvanized iron or steel.