Rod earthing, also known as earth rod or grounding rod, is a method of grounding that involves driving a metal rod into the ground to establish a low-resistance electrical connection between an electrical system and the earth.
Rod earthing consist of following points:
Grounding Rod:
A grounding rod is a metal rod, typically made of copper or galvanized steel, that serves as the grounding electrode. It is usually driven vertically into the ground, and its length varies depending on factors such as soil resistivity and the specific requirements of the grounding system.
Material and Coating for rod:
Copper or galvanized steel rods are commonly used for rod earthing due to their corrosion resistance and conductivity. Galvanized rods have a protective zinc coating that helps prevent corrosion and extends their durability.
Installation:
The grounding rod driven into the ground using specialized equipment, such as a ground rod driver or hydraulic driver. It is essential to ensure that the rod driven deep enough to establish good electrical contact with the surrounding soil.
Grounding Conductor:
A grounding conductor, often made of copper or copper-clad steel, connected to the grounding rod. This conductor carries fault currents or leakage currents from the electrical system to the grounding rod, providing a safe path to the ground.
Backfill Material:
After installing the grounding rod, the surrounding area is typically backfilled with a conductive material, such as a mixture of bentonite clay and salt. This backfill material enhances the conductivity of the soil and helps maintain a low-resistance connection between the rod and the earth.
Various electrical installations, including residential, commercial, and industrial applications use rod earthing.. It provides effective grounding to protect against electrical faults, dissipate transient overvoltages, and ensure the safety of electrical systems and individuals.
Applications of Rod Earthing
Lightning protection :
- Rod earthing used to protect buildings and structures from lightning strikes. The lightning rods help divert the lightning currents to the ground through the earth electrode/earthing rods buried underground. This protects the structure from damage.
Electrical installations :
Rod earthing is essential for electrical installations for safety. Earthing rods connected to the main earth terminals of the electrical distribution panel to provide a low resistance path for fault currents to the earth. This helps prevent electric shocks.
Substations and transmission lines :
Earthing systems installed at electric substations and around high voltage transmission lines to discharge any static charges or faults to the ground. It protects equipment and lines from overvoltages.
Telecommunications :
Earth rods used at telephone exchanges and cellular towers to divert surges or noises induced in cabling/wiring safely to ground. It protects sensitive electronic equipment.
SCADA and instrumentation systems :
Rod earthing provides common grounding reference for remotely controlled industrial instrumentation and automation systems.
Construction sites :
Temporary earth grounds installed at construction areas for equipment to prevent accidental electric shocks to workers.
Lightning protection for tall structures :
Extra long earth rods needed for effective lightning protection of very tall buildings, towers, monuments etc. due to their large surface areas.