24-04-2017, 06:08 PM
26-04-2017, 03:42 PM
Grounding is of great importance because it protects both equipment and wells than the people who use them. As its name implies grounding means equipment or installations connected to the ground. Grounding is also called earthing. The resistance of the earth is very low.
So when the equipment or installation develops a fault then the current will take the path through the ground and the equipment will remain safe. Therefore, all power supply systems, consumer facilities and electrical appliances are grounded in accordance with the Indian electricity regulations of 1972.
Now suppose that the insulation of the conductor of the inner line goes badly and v the conductor comes into contact with the metal casing, etc. If the apparatus is on a wooden table, the casing would have the same potential as the inductor, now it becomes live.
If by chance any person touches the body of the equipment and the erosion is not well insulated then the current will flow through your body and you may experience a shock, which can be fatal.
Now if the body of the equipment is properly grounded, there will be large amount of current flowing through the line due to the very low resistance of the ground and the fuse in series with the equipment will blow and the equipment will be isolated from the line .
However, at this point any person incidentally touches the equipment, the current will not pass through your body because the resistance of the body is much greater compared to the resistance of the earth. A 3-pin connector is used to ground each equipment. The third pin, which is relatively larger in diameter, is used for earthing purpose. Its value for the complete earthing system, ie the earth continuity conductor, the earthing conductor and the earthing electrode must not exceed one ohm.
Pipe Earthing
A galvanized iron tube 38 mm in diameter and 2 meters long is introduced into the ground or a copper plate of adequate size buried at the edge of the ground is used as ground electrode. Their resistance must be kept below the specified limit, powder salts and coke or charcoal to a depth of 30 cm, all around the pipe in low resistance, keeping the soil moist by pouring water into the pipe.
According to the India Electricity Rules, the frame of all motors, transformers, etc., and metal casings of all energy-consuming equipment shall be grounded by two separate and separate earth connections. In the electrical apparatus the manufacturer provides a ground termination. The foundation bolts used to hold the machines are often used to eathing them.
It can be understood in the following video: