How to reduce earth resistance?

In an electrical system, the earth’s resistance should be kept low for several reasons such as for the safety of people, protection of equipment, improved power quality, etc.

A low earth resistance ensures that stray current is safely discharged to the earth, rather than flowing through a person who comes into contact with the equipment. This helps to protect people from electric shock and other hazards. It also prevents equipment damage by providing a safe path for stray currents to flow to the ground.

Low earth resistance ensures that the earth connection is effective in providing a stable reference voltage for the system, which helps to improve power quality and reduce the likelihood of power disturbances.

Also as per many safety and electrical standards, such as the IEC standards, National Electric Code, and other local standards, it is a requirement to maintain a low earth resistance value.

There are several ways to reduce the earth resistance of an electrical system, which can help to ensure that the earth connection is effective in protecting people from electric shock and other hazards. Some common methods include:

1. Increasing the size of the earth electrode: The larger the earth electrode, the lower the resistance will be. This can be achieved by using larger-diameter rods, longer rods, or a combination of both.
2. Increasing the number of earth electrodes: The more earth electrodes that are used, the lower the resistance will be. This can be achieved by using multiple rods, or by using other types of electrodes, such as flat plates or mesh.
3. Improving the quality of the soil around the earth electrode: Soil that is moist, rich in organic matter, and well-drained will have a lower resistance than soil that is dry, rocky, or sandy. Applying fertilizers or other soil amendments, or installing a drainage system, can help to improve the quality of the soil around the electrode.
4. Enhancing the connection between the earth electrode and the equipment: The connection between the earth electrode and the equipment should be as low a resistance as possible. This can be achieved by using a thick conductor, such as a copper wire or a metal strap, and by ensuring that the connection is tight and free from corrosion.
5. Using Chemical Earthing: Chemical earthing is a process of reducing earth resistance by injecting a chemical solution into the soil around the earth electrode. The chemical solution reacts with the soil and generates a low-resistance path for the current to flow through.

It is important to note that, the earth resistance should be measured regularly and in case of high resistance, appropriate action should be taken to reduce it, as high earth resistance can lead to electrical shock, equipment failure, and other hazards.