September 12, 2016

What is the difference between Grounding and Earthing?


Difference between Grounding and Earthing:


There is no major difference between earthing and Grounding, both means “Connecting an electrical circuit or device to the Earth”. This serves various purposes like to drain away unwanted currents, to provide a reference voltage for circuits needing one, to lead lightning away from delicate equipment.

Even though there is a micro difference between grounding and earthing:


Grounding
Earthing
Definition
Grounding means connecting the live part (it means the part which carries current under normal condition) to the earth for example neutral of power transformer.
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 .
Difference in Terminology
Grounding is the commonly word used for earthing in the North American standards like IEEE, NEC, ANSI.
Earthing is used in European, Commonwealth countries and Britain standards like IS and IEC etc.
Purpose
Grounding refers the current carrying part of the system such as neutral (of the transformer or generator).
The purpose of earthing is to minimize the 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.
Balancing the Load Vs Safety
Ground is a source for unwanted currents and also as a return path for main current sometimes.
Earthing is done not for return path but only for protection of delicate equipments. It is an alternate low resistance path for current.
When we take out the neutral for a three phase unbalanced connection and send it to ground, it is called grounding. Grounding is done to balance unbalanced load.
 While earthing is used between the equipment and earth pit so as to avoid electrical shock and equipment damage.
Equipment Protection Vs Human Safety
Because of lightening, line surges or unintentional contact with other high voltage lines, dangerously high voltages can develop in the electrical distribution system wires. Grounding provides a safe, alternate path around the electrical system of your house thus minimizing damage from such occurrences. It is just a return path.
Earthing is to ensure safety or Protection of electrical equipment and Human by discharging the electrical energy to the earth. Earthing is a preventive measure.
Example
Grounding of neutral point of a star connected transformer.
Earthing of electrical equipment’s frames, enclosures, supports etc.


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