Thursday, October 10, 2013

Methods of Earthing and procedure of Earthing pit

Methods of Earthing: 

Below are the various method of earthing:-

1.Plate Earthing
2.Pipe Earthing
3.Rod Earthing

Plate Earthing:-

In this type of earthing plate either of copper or of G.I. is buried into the ground at a depth of 3 Meter or greater than 3 Meters, Earthing plate should not be buried lesser than 3 Meters.

Earthing plate is filled with layers of salt and coke not less than 1.5 feet so to provide provide lesser resistance.The earth is securely bolted to an earth plate with the help of bolt nut and washer made of copper, in case of copper plate earthing and of G.I. in case of G.I. plate earthing.
For GI earthing Plate Size should be -- 600 mm X 600 mm X 8.30 mm
For Copper earthing Plate Size should be-- 600 mm X 600 mm X 3.15 mm
Pit Size made for maintenance should be 1 Feet X 1feet so as to provide ease of accessibility of maintenance of these earthing pits and for testing of earthing pits.

Below is pictorial view for how to construct earthing pits using Plate earthing
Plate earthig method

Pipe Earthing:-

This type of earthing is used most widely in Industries. In this system of earthing a GI pipe of 30-38 mm diameter and 2 Meters length is buried vertically in ground to work as earth electrode but the depth depend upon the soil conditions, there is no hard and fast rule for this. The earth wire are fastened to the top section of the pipe with nut and bolts.The pit area around the GI pipe filled with salt and coal mixture for reducing resistance. It can take heavy leakage current for the same electrode size in comparison to plate earthing.
Pipe earthing method

Water is filled through pipe to Maintain the resistance of electrode. Pipe earthing is best form of earthing and it is also very cheap method of earthing. 

Rod Earthing:-

This type of earthing is used in area where there is soil is sandy in nature and very lesser moistened. In this system of earthing 10-15 mm diameter solid rods of copper or 10-20 mm diameter solid rod of GI pipe is directly buried in earth not lesser then 3 meters. Rod is hammered into earth for reducing resistance of earthing electrode. This system of earthing is very cheap

Rod earthing methods