Points To Remember While Providing Earthing

Points To Remember While Providing Earthing Points : points to remember while providing earthing Following point should be remembered while providing earthing to an installation and premises. Various details given as per I.S. specification are: (i) Distance The distance of the electrode from the installation at the premises should be more than 1.5 meter. (ii) Cross-section of the earthing lead It should never be less than half the cross-section of the mains wire or conductor. The selection should be made in such a way that even in worst condition it shall not fuse out. The minimum size of the earthing lead should not be less than electrical equivalent of copper conductor of 8 SWG (12.97 sq. mm cross-section). (iii) Cross-section of the earth continuity conductor The size of the earth continuity conductor should not be less than 14 SWG (2.894 sq. mm) (iv) Electrode As already discussed, the earthing can be done either with plate or pipe electrode. It should be remembered that the material for earth electrode and earth lead should be same material for earth electrode and earth lead should be same and the electrode should always be placed in vertical, position. The size of the plate earth electrode for various loads and insulation should be in accordance with the details given in Table. (v) Earth Resistance The earth resistance of any earthing should not be more than 5 ohms. As already said that for better performance at power house and sub-stations or for high horse power motor beyond 100 HP. the earth resistance should be upto 0.5 ohm and 1 ohm respectively. The resistance of earth is dependent upon area of electrode in contact with the general mass of earth, the quantity of earth, coal and salt.