Earthing is used for the safety of the personnel operat […]
Earthing is used for the safety of the personnel operating the electric device.
Earthing means connecting the dead part (it means the part which does not carries current under normal condition) to the earth for example electrical equipment’s frames, enclosures, supports etc.
The purpose of earthing is to minimize risk of receiving an electric shock if touching metal parts when a fault is present. Generally green wire is used for this as a nomenclature.
Under fault conditions the non-current carrying metal parts of an electrical installation such as frames, enclosures, supports, fencing etc. may attain high potential with respect to ground so that any person or stray animal touching these or approaching these will be subjected to potential difference which may result in the flow of a current through the body of the person or the animal of such a value as may prove fatal.
To avoid this non-current carrying metal parts of the electrical system are connected to the general mass of earth by means of an earthing system comprising of earth conductors to conduct the fault currents safely to the ground.
Earthing has been accomplished through bonding of a metallic system to earth. It is normally achieved by inserting ground rods or other electrodes deep inside earth. Earthing is to ensure safety or Protection of electrical equipment and Human by discharging the electrical energy to trounding.
Earthing literally refers to a large conducting material buried inside the soil, to which a low resistance path is provided, most commonly from the metallic bodies of electronic appliances. The earth, therefore, is considered as a giant sink where excess electrons can flow and be absorbed. For this to happen, the electric potential of the earth conductor must be higher than that of the surface where excess electrons are present. Thus, even a 0 Volt conductor is good, as its voltage is higher than other surfaces with excess electrons, which would have a negative voltage.
Earthing is done by providing a earth wire from the device to the ground. In case of faults, there is a chance that the casing of device might get current to flow in it. When a person accidentally touches that casing, he acts as a path for that current to flow through him to the ground and thus, the person gets a shock. On the other hand, if an earth wire is provided, it ensures a very low resistance path for the current to flow through it to the ground and therefore, it prevents the person from getting a shock.
Earthing is therefore, a path to a large surface of zero volt potential. This is where the earthing pin of the three-pin plug is eventually connected to. Also, lightning arresters in old houses.