WHAT IS EARTHING
What is Earthing? Can we afford to instal a earthing that is not going to serve purpose for long? Be it household or an industry, commercial installation or buildings, electrical safety is often observed compromised by inadequate earthing or problems associated to it. So we start our discussion today, with basics of earthing or grounding, and later we will focus upon the problems associated with earthings having problems.
Lets begin with What is Earthing?
As per IEC 60364-Earth:The conductive mass of the Earth, whose electric potential at any point is Conventionally taken as zero
What is the objective of earthing?
The main aim of earthing is to maintain a zero potential of all non-current carrying parts of electrical system which has the probability of accidental connection by some fault. If by some means the non-current carrying parts are electrified which is not earthed, the person touching it will receive a lethal shock.
So by earthing the non-current carrying parts are connected to earth and maintained at earth potential. It also prevents static charge buildup.
The primary functions of earthings are as below:
- Personnel safety: Personnel safety is provided by low resistance grounding and bonding between equipment, metallic objects, piping, trays and other conductive objects. The currents due to ground faults or lightning do not result in voltages sufficient to cause a shock hazard.
- Equipment and Facility Protection: For dependable functioning of over current device , to protect facility and equipment, low resistance earthing and bonding between electrical services is provided. The faults or lightning currents do not result in hazardous voltages within the facility.
- Electrical noise reduction : Electrical noise reduction is accomplished on communication circuits by ensuring that minimum voltage potentials exist between communications-electronics equipment. Also the impedance between signal ground points throughout the facility to earth is minimal.