The main reason for doing earthing in electrical network is for the safety. When all metallic parts in electrical equipments are grounded then if the insulation inside the equipments fails there are no dangerous voltages present in the equipment case.
IMPORTANCE OF EARTHING PIT IN ELECTRICAL INSTALLATION
Like other methods of earthing where iron wiĺl buried in a hole mixed with the normal earthing material need in this process a pit is dug and covered with a hole left where renewal of the eletrolyte will be possible without digging the earthing
METHOD OF CONSTRUCTING EARTH PIT
1. Excavation on earth for a normal earth Pit size is 1.5M X 1.5M X 3.0 M
2. Use 500 mm X 500 mm X 10 mm GI Plate (Plate may be use as big as possible to contact more and more area of Earth for low resistance & best result)
3. Make a mixture of Wood Coal Powder Salt & Sand all in equal part
(a) Wood Coal Powder use as good conductor of electricity, anti corrosive, rust prove for GI Plate for long life.
(b) Salt use as electrolyte to form conductivity between GI Plate Coal and Earth with humidity
(c) Sand has used to form porosity to cycle water & humidity around the mixture
4. Put GI Plate (EARTH PLATE) of size 500 mm X 500 mm X 10 mm in the mid of mixture
5. Use Double GI Strip size 30 mm X 10 mm to connect GI Plate to System Earthling
6. It will be better to use GI Pipe of size 2.5" diameter with a Flange on the top of GI Pipe to cover GI Strip from EARTH PLATE to Top Flange
7. Cover Top of GI pipe with a T joint to avoid jamming of pipe with dust & mud and also use water time to time through this pipe to bottom of earth plate
8. Maintain less than one Ohm Resistance fr
om EARTH PIT conductor to a distance of 15 Meters around the EARTH PIT with an other conductor dip on the Earth at least 500 mm deep.
9. Check Voltage between EARTH PIT conductor to Neutral of Mains Supply 220V AC 50 Hz it should be less than 2.0 Volts
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