We have heard these terms earthing and grounding so many times since childhood, and generally by our local friendly electrician who would be called at home to check on the fault. These two terms also used interchangeably at times have completely different working modes and purpose. Today we will be checking out the major differences between the two.
1. Earthing refers to connecting the non-functional parts of an electrical device to the ground i.e. the parts where there is no actual electricity is being passed whereas grounding refers to the process of connecting live parts of a device to the ground or earth.
2. Earthing is done to provide a level of protection to the humans and animals in case they come in contact with a part of device which when faulty can create a potential difference between the device and ground hence leading to a fatal shock to the creature, whereas grounding is done to protect the delicate circuits and systems of a device from sudden faults that may damage them.
3. Earthing as discussed is a protective measure for safeguarding lives at times we would observe all tall buildings equipped with a lightning rod that acts as an earthing measure for the entire building hence protecting the building and inhabitants from huge electrical energy generated from thunderbolts whereas grounding may or may not be directly connected to earth. In some cases, grounding is done by connecting the device to a transformer neutral also.
4. A green wire, in general, denotes earthing whereas a black wire is used for denoting grounding.
5. Earthing may or may not be used or utilized and its usage depends on the application, For example in case of vehicles electrical systems only grounding is done and the excess surge protection is achieved by connecting the devices to vehicles chassis. In some cases like in case of fuel tankers, additional metallic chains are employed to ground the static which otherwise might lead to a deadly static charge being formed.
6. In the US terminology grounding is used whereas in UK earthing is used. We are mentioning the common parlance here.
7. Earthing is a one-way process where the excess stray current is discharged into earth, there is no return path for current in case of earthing its merely for protection. whereas grounding is done to act as the return path for current, here the excess current is discharged and the requisite value of current is sent back to the system for its efficient use.
8. In technical terms when the neutral from a three-phase system which is in an unbalanced condition is removed and the current is sent to ground in order to bring the entire system back to balanced conditions then the phenomenon of grounding has taken place whereas earthing helps to protect the device and human life by just discharging the extra charge in to ground.
9. In even simpler terms earthing is a protective measure whereas grounding is a functional measure which defines the return path of the current.
10. Earthing and grounding both, in theory, have zero potential, but the difference lies in the fact whether a particular device is connected to zero potential or a system is connected to zero potential. if the neutral point of a transformer is connected to zero potential then it can be termed as grounding as a return path is set, whereas if the body is of the same transformer is connected to the zero potential in the earth/ground pit then it is termed as earthing.Grounding is done to protect the transformer from internal surges whereas earthing will protect the structure of transformer from external as well as internal faults.