Earthing or Grounding System
By Hudson Engineering
Earthing means connecting the neutral point of a supply system or the non –current carrying metal parts used in electrical distribution system to the general mass of earth by wire of negligible resistance in such a manner that at all times an electrical discharge of electrical energy takes place without danger. This brings the body of the equipment to zero potential and thus will avoid the shock to the operator.
Purpose of Earthing:
- To avoid electrical shock to human body.
- To avoid risk of fire due to earth leakage current through unwanted path.
- To ensure that no current carrying conductor rise to potential with respect to earth than its designed insulation.
Important term used in Earthing
A conductor or group of conductors in intimate contact with and providing an electrical connection to earth.
Earth Electrode Resistance:
The resistance of an earth electrode to earth.
The potential difference between a grounded metallic structure and the point on the earth’s surface separated by a distance equal to the normal maximum horizontal reach approximately one meter.
The potential difference between two points on the earth’s surface separated by a distance one pace, that will be assumed to be one meter in the direction of maximum potential gradient.
A system of grounding electrodes consisting of inter¬ connected connectors buried in the earth to provide a common ground for electrical devices and metallic structure.