Earthing and purpose of earthing

 

What is earthing and purpose of earthing

 

The process of connecting metallic body of all the electrical apparatus and equipment to the huge mass of earth by a wire of negligible resistance  is called earthing .

The basic purpose of earthing is to protect the human body from the electrical shock. If human body touch the charged electric body where as earthing is parallel in human body .where earthing formed  by pass path of electric charge from the electric body . When earth fault occur live or phase wire contact with  outer body. Where as almost whole current passe through earth by earthing. 

TYPE OF EARTHING

1 . Strip earthing :- 

                                   The system earthing is employs the use of 5 SWG copper wire or strip of  earthing not less then 25mm x 16mm the strip of wire are buried in horizontal  trenches .  This type of earthing is used where the earthing bed has a rocky soil .

2. Earthing through water mains:- 

                                                             In this earthing a stranded copper lead is used that is rounded on the pipe with the help of steel binding wire and a properly designed earthing clip . The copper lead is fixed to make it solid before making connection to wire main, it should be ensure that GI pipe is used through out. 

3. Rod Earthing :-

                                 It is cheaper method of earthing and it employed in sandy areas in this method a copper rod is hammered directly in to the ground and there are no excavation work is required the earthing lead is joined  to this rod with help of nut and bolts. 

4. Pipe earthing :-

                                   Taking in to consideration the factor such as initial cost inspection resistance measurement etc. G I pipe earthing is best from of ground connection iron is cheapest material and also serviceable even if put in salty mass of earth. The pipe used as earth electrode is galvanised and perforated . Its diameter is 38.1mm and length is 2m. The length may be increased to 2.75m in case of dry soil . the earth lead should be connected to pipe.

5. Plate earthing :- 

                                   In this earthing copper or GI plate dimension not less then 60cmx 60cm.3.18mm or 60mmx 6.35mm is used as earth electrode instead of GI pipe . The plate is buried in the ground level. GI wire is used for GI plate and copper wire used for copper plate earthing. The size of wire is selected according to the instalation and fault current alternate layer of charcoal and salt is used . It maintain the stable moisture.