Earthing

Earthing is a traditional and efficient way of transferring and immediately discharging of electrical energy to the earth directly through a low-resistance wire. We have seen that a normal plug consists of 3 pins. These pins are live, neutral, and earth pins. This earth pin is the main pin used for transferring extra charge from devices and thereby protecting the device. The pin transfers extra charges to earth through low-resistance wire avoiding any major shock. Thereby Earthing is a major process used in electrical engineering.

In this article, we will learn about earthing, its needs, and its various types. First, we will start our Article with the definition of earthing then we will also discuss the components needed for earthing and various ways of testing and managing it. At last, we will discuss some advantages, disadvantages of earthing and We will conclude the article with some Frequently Asked Questions.

What is Earthing?

Earthing is a process in which the leakage current is made to flow to the earth to prevent the accumulation of excess current in a device. Thereby it prevents any major shock or fire due to static charges. In scientific terms, we can define earthing as :

The process in which the sudden discharge of the electric current takes place by transferring charges directly to the earth’s ground using a low resistance wire.

This is a simple process that saves devices from any damage. Transferring huge fault currents into the earth, prevents any major shock in electric components.

Earthing

Need for Earthing

Earthing is used for security and overall functionality in electric components. In case of situations like lightning, major voltage surge the current flowing in a device exceeds the optimal value. This can lead to disastrous situations like fire due to static charges, huge electric shocks causing damage of the device. To avoid any such serious mishap , we use earthing.

The excess current called fault current is made to flow into earth ground which acts as a neutral plate. This ensures there is no deposition of excess current on devices and hence earthing protects devices from getting damaged. Hence, earthing serves several important purposes by contributing to the safety, reliability, and proper functioning of grounding systems.

Types of Earthing

Earthing can be divide into these major types:

• Pipe Earthing
• Plate Earthing
• Strip Earthing

Pipe Earthing

When we require an economical way of security we use this type. It uses a galvanized steel perforated pipe which is buried in the ground. The vertical alignment of the pipe ensures all components connected to it are grounded.

Pipe Earthing

Plate Earthing

As the name suggests , this type of earthing involves a metal plate buried in ground which serves as earthing electrode. The plate material is usually made up of a galvanized copper or iron plate , the size and depth of plate are decided by factors like soil resistivity. The plate connects all the conductors to the earth.

Plate Earthing

Strip Earthing

A wire or long strip of metal is used as electrode which are buried horizontally in the ground. These strips are useful in the procedure of transmission. It is often used in industrial areas where space is limited or where larger surface area is available.

Strip Earthing

Types of Electrical Earthing

Electrical Earthing is done by establishing connection between non-current carrying part of equipment or supply to the ground. We can further divide it into two types namely neutral earthing and equipment earthing which have been explained below. Here is the diagram to show the electrical earthing :

• Neutral Earthing
• Equipment Earthing

Electrical Earthing

Basically there are two types of electrical earthing :

Neutral Earthing

In this, neutral of the system is directly connected to earth with the help of a GI(Galvanized Iron) wire. Most common usage of this earthing is in appliances which require star winding. We also call this type of earthing as system earthing.

Neutral Earthing

Equipment Earthing

In this type of earthing, the non-current carrying part of equipment is connected to earth ground with the help of a conducting wire. In case of any fault, the short-circuit current passes through the wire to earth avoiding any mishap. This is the most common earthing provided to electronic equipment.

Equipment Earthing

Earthing Components

Grounding system is significant for electrical engineering and is designed to provide a low resistance path for excess current to flow into earth. Thereby these systems are installed to prevent any mishap. The components of a grounding system include earthing electrodes, earthing conductors, and earthing bonding.

• Earthing electrodes: These are metal rods installed in earth ground to provide a path which has low resistance. The effectiveness of these rods depends on the material from which it is made and the soil resistivity. Earthing electrodes can be made of copper rods, galvanized steel.
• Earthing conductors: These are conductive material that is used for connecting various metallic components of an installation to the earthing electrode in ground. They help preventing shocks by preventing build-up of dangerously high voltages. They are usually made up of copper and aluminium.
• Earthing bonding: This bonding ensures all components of installation remain at the same potential. This help to ensure there is no sparking by connecting all components together. This mainly uses bonding conductors made of copper or aluminium, to connect metals and equipment together.

Components of Earthing

Procedure of Earthing

In household earthing is done by connecting electrical appliances to an earthing system. The electrode or metallic strip consisting of flat iron riser is placed at a certain depth in ground(earth). This electrode connects all metallic components which don’t carry current together. During a fault or major current, the fault current from appliances flows into earthing system. The earthing conductors help to normalize the voltage level. The resistance of earth wire helps as a guard and prevents the breakdown of devices. In plugs, there are three types of wires, live, neutral, and earth. The live and neutral wires carry electric current whereas the earth wire is connected to the buried metal plate in ground.

Earthing Testing And Maintenance

After installing an earthing system, it is necessary to test and maintain it as well to ensure the reliability of electrical appliances. This test and maintenance can be done by:

• Soil Resistivity test: It becomes mandatory to regularly inspect the soil in which the earthing system is placed. We regularly search for any traces of change in PH and other soil conditions.
• Inspection: Periodic checks of the earthing system is necessary to make any change in the system before any major flaw occurs in the system. We often look for physical damage, corrosion, or loose connections. This also includes checking the state of electrodes being used.
• Fall-of-Potential Test: This test is done to measure earth resistance of grounding system . In this a known amount of current is flown through earth and voltage drop across the earth electrode is measured.
• Galvanic Corrosion Protection: Protection from corrosion is necessary for maintenance of electrodes. This is done using corrosion protection measures since it involves using corrosion resistant material.

Now these testing and regulation methods are necessary to identify any potential issue and take necessary actions accordingly.

Difference Between Earthing and Neutral

Lets compare the difference between neutral and earthing:

Earthing	Neutral
It helps to eliminate any damage due to leakage current by providing a low resistance path.	Neutral is a conducting wire used in AC circuit that provides returning path for flow of electric current.
It doesn’t carry current but minor electricity due to disconnections.	As opposed to earthing, it always carries current.
This is the grounding point for flow of electric current.	It provides returning path for flow of electric current.
An earthing connection can execute independently or with the help of a neutral wire.	It is connected to a neutral line.
Earth point is a surging point of appliances.	Since it is a return path ,it is called a reference.

Advantages of Earthing

There are some major advantages of earthing:

• It prevents the risk of major fires and electric shocks caused due to current leakage in appliances.
• In case of a Voltage Surge i.e. an overload in voltage, there is no major mishap due to earthing. This is because extra carriers generated due to voltage surge are sent to earth.
• Earthing ensures safety at home. Due to earth being neutral, any extra shock is sent to earth thereby keeping appliances safe for use.
• Buildings remain safe in-case of lightning, when light shock falls on a building , the conducting body sends the current to earth through a low resistance wire.
• Earthing minimizes electrical noise and interference in audio and video systems, ensuring better signal quality.

Disadvantages of Earthing

These are some disadvantages of earthing:

• Due to collection of excess electrons in ground, the natural nutrients of soil get depleted , thereby making soil unfit for cultivation , disturbing the natural vegetation.
• Although earthing requires minimal maintenance, there is always a chance of earthing line getting tarnished with time. In this case the resistance of electrical wire increases ,reducing the effectiveness of earthing system.
• Negligence while installing earthing system can result in various hazards. This can provide users with a sense of security despite there being no security due to improper grounding.
• The task of designing an earthing system is very complicated resulting in high maintenance and installation cost.

Applications of Earthing

Earthing is almost included in all electrical appliances like:

• It is used for protection of buildings from lightning by sending the electric current directly to earth.
• It is often used in electronic devices to reduce the noise generated. Thereby earthing is used for noise reduction purposes.
• Earthing is used at hospital facilities, by performing potential equalization in devices. It is very necessary to maintain voltages in hospital machines therefore earthing is used for preventing any dangerous voltages in devices.
• It is used for prevention of any mishap like electric shock or major fires caused due to static charges. Hence it is used for protection of static buildings from static spark.
• It is used for earth fault detection. Earthing lines are installed at secondary-side of power transformer, this provides a path for earth fault current to flow.

Conclusion

In this article, we have seen how earthing is an important phenomena for protecting devices in various scenarios. Installation of earthing appliances is a meticulous task and needs extra precaution and cost. There are certain precautions that must be taken while dealing with earthing appliances. Scientists and researchers have made great advancement in this field to ensure proper safety and deal with hazardous situations like lightning and Voltage surges. Earthing forms backbone of modern electronics.

FAQs on Earthing

What is grounding? How does it differ from Earthing?

Grounding means connecting the live part, it means the constituent that carries current under normal condition to the earth. In earthing, the circuit is physically connected to the ground, which is Zero Volt Potential but in grounding the circuit is not physically connected to the ground, but its potential is zero with respect to other points.

Is earthing a pros or a cons?

Earthing has its own cons like high cost and maintenance but despite this it serves one major advantage of providing security in appliances therefore it becomes inevitable in electronics.

Which rod is used for the procedure of earthing?

We can use earth rod for earthing.

Why is salt used in earthing?

Salt helps to maintain low resistance in wires in-case of moisture and fault currents.