In this, cast Iron plate of size 600 mm × 600 mm × 6.3 mm thick plate is being used as earth plate. This is being connected with hot dip GI main earth strip of size 50mm breadth × 6mm thick × 2.5 meter long by means of nut, bolts and washers of required size. The main earth strip is connected with hot dip GI strip of size 40mm × 3mm of required length as per the site location up to the equipment earth / neutral connection. The earth plate is back filled and covered with earthing material (mixture of charcoal & salt) by 150mm from all six sides. The remaining pit is back filled with excavated earth. Along with earth plate, rigid PVC pipe of 2.5 meter long is also provided in the earth pit for watering purpose for to keep the earthing resistance within specific limit.

In this method hot dip GI pipe of size 40 mm dia × 2.5 meter is being used for equipment earthing. This pipe is perforated at each interval of 100mm and is tapered at lower end. A clamped is welded with this pipe at 100 mm below the top for making connection with hot dip GI strip of size 40mm × 3mm of required length as per the site location up to the equipment earth / neutral connection. On its open end funnel is being fitted for watering purpose. The earth pipe is placed inside 2700 mm depth pit. A 600mm dia “farma“ of GI sheet or cement pipe in two halves is are placed around the pipe. Then the angular space between this “farma” and earth pipe is back filled with alternate layer of 300mm height with salt and charcoal. The remaining space outside “farma” will be backfilled by excavated earth. The “farma” is gradually lifted up as the backfilling up progresses. Thus the pit is being filled up to the 300mm below the ground level. This remaining portion is covered by constructing a small chamber of brick so that top open end of pipe and connection with main earth pipe will be accessible for attending when necessary. The chamber is closed by wooden/stone cover. Water is poured into the pipe through its open end funnel to keep the earthing resistance within specific limit.

When the capabilities of certain equipment are limited, they may not with stand certain fault currents then the following types of earthing are resorted to limit the fault current.

1. Resistance earthing
2. Reactance earthing
3. Peterson coil earthing.
4. Earthing through grounding transformer.