What is Electrical Earthing : Different Types & Its Components

Most of the engineers like electrical, electronic, or civil use electrical earthing for protecting the buildings, equipment from some breakdowns or damages, but the safety of an operator is the most essential element. The AC line troubles can be protected by a proper earthing. It is also the main element for avoiding RF intrusion in communication. Furthermore, the quality of power can be drastically corrupted due to faulty earthing. Executing an electrical earthing is not a simple job. It requires skilled operators with proper planning and quality devices. However, the right electrical earthing is an asset that will provide compensation for the facility of life.

What is Electrical Earthing System?

Earthing is the method of transmitting the instant electricity discharge directly to the ground through low resistance wires or electrical cables. This is one of the significant features of electrical networks. Because it builds the most eagerly accessible and hazardous power source much secure to utilize.

In the process of earthing in case of short circuit condition, the electrical wire carefully removes the overflow of current and allows it to flow through the earth. All this occurs without unnecessary problems, only through resourceful and inexpensive manufacture, plan as well as arrangement!

Why Electrical Earthing is Required?

The main intention of electrical earthing is to keep away from the danger of electric shock due to the outflow of current from the ground through the not preferred path as well as to make sure that the potential of a conductor does not increase with respect to the ground than its planned insulation.

When the metallic element of electrical machines approaches in contact with an existing wire, due to a breakdown of fixing the cable, the metal turn into charged and static charge collects on it. If someone contacts such an electric metal, then the outcome is a severe electric shock. So finally

We can conclude that life is random, and one should always get ready for unexpected circumstances. So buildings and electric appliances have to be grounded to transfer the electric charge directly to the ground. The main benefits of grounding include protection from overvoltage, stabilization of voltage, and prevention from injury, damage, and death.

Specifications of Electrical Earthing

According to ISI, the required specifications for providing good earthing include the following.

• The arrangement of the earthing electrode can be done at minimum1.5 meters distance away from the outside where the installation system is earthed.
• The material used for the earth electrode must be the same as an earth wire. The least sectional region of earth lead wired should not be low as compared to 0.02 sq. inch & not above 0.1 square .inch.
• According to a normal rule, the earth conductor size must be low as compared to the line conductor’s half of the section.
• The earth wire must be removed using a 1mm diameter of G.I pipe from a minimum 32cm length below & above the surface of ground toward the earth electrode to defend from mechanical wear & tear.
• For efficient earthing, coal salt mixture & loose earth must be filled in the region of the earth electrode.
• In the earth wire, all the connections must be tightly done using bolts and nuts of a similar material like an earth wire.

Components used in Electrical Earthing System

The main components used in the earthing system mainly include earth cable, earthing joint (earthing lead), and earth plate

Earth Cable

The conductor is used to connect metallic parts of an electrical system like plug sockets, metallic shells, fuses, distribution boxes. Metallic parts of motors, transformers, generators, etc. the range of these conductors depend on the earth cable size used in the wiring circuit. The earth wire in the cross-sectional area must be less than the solid wire used in the electrical wiring system.

In general, the copper wire utilized as an earth continuity conductor size is a 3-standard wire gauge (SWG). Ground wires which are smaller than 14-SWG should not be used. In some situations, copper strips are used instead of a bare copper conductor.

Earthing Joint

The ‘ground electrode’ as well as conductors fixing to the ‘ground continuity conductor’ is called earthing joint (earthing lead).  The tip where the earthing joint connects the ground continuity conductor is known as the connecting end. The lead of the ground must be low size, straight, & should include a minimum amount of joints. Although copper wires are usually used as grounding leads; whereas copper strips are selected for high fitting because it carries high fault current values due to its broad region.

Earth Plate

The last part of the electrical grounding system which is hidden underground and linked to the lead of grounding is known as the earth plate. Earth electrode is a pipe, plate, or metallic rod, or plate; which has extremely low resistance for carrying the fault current to the ground safely.

It can be of iron or copper rod and must be placed in wet earth and in case the moisture content of the earth is low then put some water in the earth plate. The earth plate is always placed in the vertical, and coat with salt and charcoal lime around the earth plate. This helps in protecting the earth plate as well as in maintains ground moisture around the earth plate. The earth plate must be placed four meters long for better earthing.

Types of Electrical Earthing Systems

The process of Earthing or electrical grounding can be done in several ways like wiring in factories, housing, other machines, and electrical equipment. The different types of electrical earthing systems include the following.

Plate Earthing System

In this type of system, a plate is made up of copper or GI (galvanized iron) which are placed vertically in the ground pit less than 3meters from the earth. For a better electrical grounding system, one should maintain the earth moisture condition around the plate earthing system.

Pipe Earthing System

A galvanized steel-based pipe is placed vertically in a wet is known as pipe earthing, and it is the most common type of earthing system. The pipe size mainly depends on the soil type and magnitude of the current. Usually, for the ordinary soil, the pipe dimension should be 1.5 inches in diameter and 9feets in length. For rocky or dry soil, the pipe diameter should be greater than the ordinary soil pipe. The soil moisture will decide the pipe’s length to be placed in the earth. The pipe earthing diagram is shown below:

Rod Earthing System

This type of earthing system is similar to a pipe earthing system. A copper rod with galvanized steel pipe is placed upright in the ground physically or using a hammer. The embedded electrode lengths in the earth decrease the resistance of the earth to a preferred value.

Neutral Earthing

In this type, the system’s neutral is connected directly toward the earth using GI wire. The alternate name of this system is neutral earthing and this kind of earthing is generally given to the system which contains star winding. For instance, this earthing is offered in transformer, the generator, motor, etc.

Equipment Earthing

This kind of earth is given to electrical devices. The device that doesn’t carry current like a metallic frame is allied to the earth using the conducting wire. If any error occurs within the device then the short-circuit current will be supplied to the earth by using wire to guard the system against injure.

The procedure of Electrical Earthing

For electrical earthing, the following objects are used and its quantity mainly depends on the utilization of power as well as duration.

• Charcoal
• Underground Power Cable based on distance from the electric pole to the meter panel
• Industrial Salt
• Copper Wire
• MS Earthing Pipe
• Copper Plate

For example, rod-based electrical earthing installation can be done like the following.

• Dig the soil deeply with 6 feet & 2 x 2 feet broad in close proximity to the electrical meter panel
• Place the copper plate at the corner of the MS rod with the help of copper bolts & cover it by using copper wire.
• Arrange the pipe in a vertical position using a copper plate at the base
• In the empty part of the MS pipe & around it, fill the salt.
• Place charcoal nearby to the pipe.
• Pour concrete mixture and sand around the pipe.
• Repeat the above last three steps many times till the pipe gets filled the fixed level
• Place the copper wire on top of the pipe so that it can be allied to a suitable place within the meter panel.
• One pipe or MS rod can be connected at the side of the electric pole & the other can be connected at the side of the meter panel.

The qualities of good earthing include the following.

• It should be of less electrical resistance
• Good corrosion resistance
• It should be capable of dissipating high fault current frequently

Difference between Earthing, Grounding & Bonding

There is confusion to know the main concepts of earthing, bonding & grounding. Sometimes even some professionals changed the meanings of these terms like earthing bond, bonding ground, etc. Additionally, electrical bonding is completely dissimilar as compared to earthing & grounding because these two concepts are the same which are expressed through different terms. The main difference between these three includes the following.

In the USA, the term Grounding is mainly used for Earthing & Canada based on CEC, NEC, UL, IEEE, and ANSI standards. In Grounding, the live part is connected to the earth and the best example of grounding is a neutral power transformer.

In UK, EU & other countries, the term Earthing is used who follow the standards of IEC & IS. In Earthing, the dead part is connected to the earth and the best example of Earthing is frames of electrical equipment, supports, enclosures, etc.

The term bonding is used in different countries like UK, US &EU for jointing two conductors like pumps, wires, machines, etc & metallic bodies to level the potential disparity on both systems or machines connected through bond wire. Bonding is mainly used to connect two electrical conductors like a wire & a pipe otherwise two types of equipment.

Different Terms used in Electrical Earthing

In electrical earthing, different terms are used which are discussed below.

Earth

Earth is the proper connection among electrical installation systems through conductor toward the covered plate within the earth

Earthed

Once an electrical appliance is connected toward the earth using an earth electrode, then it is called an earthed device.

Solidly Earthed

Once an electric device is connected toward the earth without using a circuit breaker, fuse or Impedance/ resistance is called solidly earthed.

Earth Electrode

Once a conductor is covered within the earth used for the electrical earthing system is called as Earth Electrode. These are available in various shapes such as conductive rod, conductive plate, metal water pipe otherwise any other conductor through less resistance.

Earthing Lead

When the conductive strip is connected among the Electrical installation system & Earth electrode then it is known as Earthing lead.

Earth Continuity Conductor

When the conductor wire is connected among different electrical devices is known as an earth continuity conductor. The shape of this conductor is like a metal pipe or flexible wire or cable metallic sheath.

Sub Main Earthing Conductor

A wire is connected among the distribution board & switchboard, then the conductor is associated to sub-main circuits.

Earth Resistance

The whole resistance among earth electrodes as well as earth in ohms is known as earth resistance. This resistance is the sum of the resistances of earthing lead, earth continuity conductor, earth & earth electrode.

Codes in Earthing System

Earthing systems are available in different types which are represented through codes for different purposes. The system properties are mainly used for electrical installation. In the code, the initial letter denotes the main connection of the distribution system toward the ground either I or T. The next letter in the code denotes the main relationship of the fixed exposed-conductive parts toward earth.

The ‘T’ specifies that the exposed-conductive elements are earthed directly & independently at any end of the power system. Here, ‘N’ means that a conductor with low impedance can be detached from the connection of earth at the source, after that it is connected to the exposed conductive parts. Further, ‘N’ is sub-divided into two letters like C & S.

Electricity Rules for Earthing

The electricity rule for earthing mainly includes the following.

• In house wiring system, the earthing should be continuous through a single solid conductor. The main switch, electrical equipment, distribution box, ceiling fans with the walls socket’s earth must be earthed.
• The earth continuity conductor’s resistance should not be above 1 ohm during the system.
• All the machine metallic covers including average voltage must be earthed through two separate earth connections.
• The electrodes earth resistance should not go beyond three ohms for normal earth. The resistance of the earth for the electrode should not go beyond eight ohms for rocky soil.

What is the Function of Earth Wire in Electrical Instruments?

• The electric appliance’s metallic body can be connected toward the earth with the help of earth wire so that electric current any leakage can be transmitted toward the ground. This avoids electric shock for the human being.
• Here, the connection of the metallic body can be done with the earth wire that gives a less resistant conducting lane for the current. Therefore, it guarantees that any current leakage toward the metallic body of the appliances will keep its possible to the earth, so the user may not get an electric shock.
• Grounding wires provide an alternate path for the current supply to flow back to the source instead of supply throughout anyone handling a hazardous appliance otherwise electrical box.
• Some appliances like electric drills and vacuum cleaners do not include an earth wire. The earth is in an attractive position for electric supply as it is charged positively.

How Earthing Reduces Electricity Bill?

Actually, Earthing is one kind of method where some additional voltage is not necessary through the appliance and this voltage can be transmitted toward the Earth through a wire. So this will help in decreasing chances for overloading & conserves extra current. So it really decreases your electricity bills.

Affecting Factors while Earthing Installation

There are different factors that affect while earthing installation are discussed below.

• While earthing installation, several factors play a key role which must be taken into consideration for any type of calculation regarding the kind of earth, the type of circuits necessary, etc
• The effectiveness of earthing can be decided based on the type of soil like resistance, level of moisture, salts within the soil. Another factor that needs to take into consideration is soil composition. For instance, as compared to wet soil, rocky soil has to be treated very differently.
• The final factor is the earth pit’s location so that we can decide how the earthing installation must be done. If there are obstacles in the underground in the rock beds form, then this will be another factor that will affect the earthing installations.

Advantages

The advantages of Earthing system include the following.

• It provides safety for electrical devices and appliances from the extreme electric current.
• It helps in avoiding the risk of fire in electrical installation systems.
• It helps in the electric current supply directly in the ground.
• It prevents the death caused by electric current.
• Electric appliances can be protected from the damage
• Earthing provides protection from overvoltage and voltage stabilization.
• It protects from fire occurred because of the electric short circuit so that goods can be protected from fire.
• From the lighting, it defends building breakdown.
• It provides a simple path even after the insulation failure to the short circuit current supply
• It provides surge protection and protects from electric shock
• It gives protection to the apparatus from lightning discharge and high voltage surges
• The Earthing assists in detecting any fault in phase & neutral conductors.
• Earthing assists to get rid of the fire risk otherwise detonation throughout insulation fault.

Disadvantages

The disadvantages of Earthing system include the following.

• Hard to place line-to-ground fault
• Doesn’t control transient overvoltages
• Maintenance cost is high because of the labor involved in placing ground faults.

If the earthing system is not implemented then there are some drawbacks

• If earthing is not used for houses, there is a chance to get an electric shock.
• The switches used for protection will not work properly. Thus, any error can cause damage to appliances.
• Appliances may get damage during fault or short circuit or lightning conditions. So this can reduce the working condition of home appliances or equipment.

Applications

The applications of electrical earthing include the following.

• Earthing protects from an electric shock by providing a lane for a fault current to supply toward the earth.
• Earthing causes the protecting device to disable the flow of current toward the fault circuit
• The earth wire function is to perform the leaking current from the device to the earth and is connected to the appliance’s external metallic body.
• It is essential for earth metallic appliances because it guards the operator against electric shocks by supplying the current supply toward the ground.
• Once the insulation fails or a short circuit occurs then it protects the devices as well as the operators
• It functions as a circuit breaker once the wire strikes the earth wire then huge current supplies throughout it.
• Lightning conductor utilizes Earthing while the lightning metal rod is attached to the metal plate to defend the people & building

This is all about an overview of grounding or what is meant by earthing/definition of earthing and its types. From the above information, finally, we can conclude that the earthing system or electrical grounding system offers greater safety from electric shock for personal, equipment, buildings, etc. The ground sensitivity can be The earth resistivity can be affected by some issues like soil and climate, a condition of resistivity, moisture, melted salts, earth pit location, physical work, grain size effect, current magnitude, etc. Here e is a question for you, what are the benefits of electrical earthing?

Photo Credit – Types of Earthing