Importance of Earthing in Electrical system
Earthing is a connection between electrical devices to the earth through a low resistance path, which provides discharge of the electrical energy directly to the earth. Considering the safety reasons earthing is one of the main safety requirement in an electrical system.
Why earthing is necessary for electrical systems?
Minimizes risk of electric shock: The main purpose of earthing is to avoid or minimize the chance of electrocution. Any leakage or faulty current in the circuit causes the presence of electric charge on exposed conductive surfaces. Earthing provides a low resistive conductive path directly to the earth, which carries any such fault or leakage current.
As the earth line is always in contact with the earth, the entire point of the earth conductor will not have enough potential to cause an accident. That is no potential difference to cause a serious amount of current flow through another path, for example, a human body. Hence, the metal parts, chassis of the device, etc., which are connected to the earth line will be always safe to touch. So, It is better to earth any non-insulated body of the electrical appliances which may have a human contact. Also, it is recommended to provide earthing for appliances which have contact with water or liquids.
So earthing is essential to protect human lives as well as provide safety to electrical devices and appliances.
Dissipation of static charge: In a perfectly earthed system its potential remains approximately equal to zero. So it can remove most of the static charge build-up in the conductors.
Eliminate stray voltage: Similar to static charge it also prevents stray voltage in the line. That is no potential difference to build in the conductor.
Voltage Stabilization: In a network which has multiple feeders or sources there must be a common point which acts as a universal reference point. The Earthing acts like as a balance point.
Protection from power surges: Earthing can protect from sudden excessive surges, it also provides protection from lightning strikes. Any lighting strikes on the exposed metal or received through another path which is connected to earth line get discharged directly to earth.
For proper functioning of equipment’s: Proper earthing is very important for the functioning of the devices connected to the system. Mainly protective devices like ELCB, earth fault relays, etc. needs proper earthing for its functioning. Because in order to operate all these devices use the reference of leakage current through the earth line.