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Every one of us has heard the term “electrical grounding" several hundred times. However, the concept of grounding is so loosely understood that if you ask “what is grounding?" to five different people, there is a high probability that you will get five different answers.
Electrical grounding, electrical ground, and earthing are few different names for the same concept. Grounding is an essential part of all electrical systems and is extremely important from safety point of view. In the article we will try to explain you everything you ever wanted to know about “electrical grounding."
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What is Electrical Grounding?
Electrical Grounding basically means the involvement of earth in an electrical system. For instance, if you open up any electrical equipment or even a small electrical plug, you will always find a wire which acts as an “earth connection." Ever wondered why?
Our planet earth is a very good conductor of electricity. Moreover, as it is huge in size, it acts as an infinite sink for the charge or electrons. Thus, when we say “electrical ground," the word “ground" literally means the earth surface below us. The ground is thus the direct physical electrical connection of the electrical equipment to the earth.
Want to detect grounding in an electrical system? Have a look at any utility pole in your locality and you will be able to spot a separate wire coming down from one of its sides and going into the ground. The wire is often connected to the ground using a copper coil or rod, buried few meters under the ground. An earthing wire can also be found near the electrical meters of your homes.
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Understanding Electrical Grounding
There are several reasons for doing electrical grounding; however, the foremost reason is for the safety of the user and electrical equipment. It is known that all the electrical equipment have some or the other metal parts which are exposed to the atmosphere. These exposed parts can act hazardous if there is no proper earthing provided in the system. In case the grounding fails, a voltage build up occurs between the earth and the electrical circuit. At this time, if someone comes in contact with the exposed metal part, the electrons flow through him, resulting in an electric shock.
However, there is a difference. If a person touches an exposed metal part but none of his body part is connect to the ground then there would be no electric shock. It is only when the person is barefoot and comes in proper contact with the earth that the transfer of electrons through his body takes place. A human body is also a good conductor of electricity and thus the transfer of electrons takes place through it. Thus no matter what wire a person touches, live or neutral, he wouldn’t experience a shock unless he is directly connected to the ground.
Apart from this, electrical grounding is also used for measurement purpose. The earth is used as a reference voltage against which voltages of all the electrical systems are measured and adjusted. Thus an electrical grounding not only serves as a reference level, but also as an electrical sink which can absorb unlimited electrons without any change in its voltage.
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Three Main Purposes of Electrical Grounding
To sum it up, electrical grounding serves three main purposes:
Protection from over voltage
The voltage of a system sometime rises drastically when it comes in unintentional contact with a higher voltage source such as lightening and voltage surge. In such cases, grounding provides an alternative path to the system for the transfer of the additional voltage to the ground, preventing any kind of damage.
Voltage measurement and stabilization
Grounding helps in taking earth’s voltage as the reference for adjusting voltages of various parts of the electrical system. The setting of voltages in different parts also helps in drawing a relationship between various parts of the system.
Protection to equipment and for humans
The most important aspect is that electrical grounding helps in protecting electrical equipment and humans from any kind of voltage rise in the electrical system.
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Grounding is done in all the systems that deal with electricity, irrespective of their location. This means that grounding of electrical equipments is done on ships in sea water as well as in flying aircrafts. Moreover, grounding is also done in radio communication systems, wherein the earth connection serves as a reference potential for radio frequency signals of different antennas.