What is maintenance free chemical earthing?
This type of earthing arrangement requires no maintenance so called as “Maintenance free earthing or “Effective Earthing”. Effective earthing electrode eliminates problems of conventional earthing: 1. By providing highly corrosion resistant Earthing Electrode.
What is chemical earthing system?
Chemical Earthing is a traditional earthing system whereby chemicals are added to earthing pits such as bentonite or graphite-based compounds used that helps in improving the condition of the soil and reducing the soil resistivity.
How do you maintain the chemical earth pit?
The pit is excavated and the electrode is placed in the centre and is filled with soil, mixed with salt and charcoal. The conduction of current in the conventional electrode is electrolytic. Hence, regular watering and charging of the earth pit with salt is very essential to maintain low earth resistance.
Which powder is used for chemical earthing?
Bentonite
Bentonite is used to lower the resistance to earth by providing ground enhancement effectively reducing the resistance between the soil and earth electrode (such as copper earth rod or earth mats) by retaining moisture.
What is strip earthing?
Strip or wire earthing. Plate Earthing. In this type of earthing, a plate made up of galvanized iron or copper is buried vertically at a depth not less than 3m from the ground level.
What is Rod type earthing?
Earth Rods are a type of Earth Electrode. An Earth Electrode is a conducting element buried directly in the ground, facilitating the flow of fault currents towards the ground. These Rods are also commonly referred to as Ground Rods in North America.
How many types of chemical earthing are there?
Two types of powders are used in chemical earthing. One is Carbon powder and the other is Bentonite powder. Carbon powder is black in color while bentonite powder is brown in color. Earthing with carbon powder is used in a normal place while earthing with bentonite powder is used in a dry place.
How can chemical earthing be improved?
The most effective methods are to increase the depth of the electrode, place several electrodes, and perform a chemical treatment to the soil near the electrodes. Increasing the diameter of the ground rod does not result in a significant reduction in resistance to ground.
What is the best earthing value?
Ideally a ground should be of zero ohms resistance. There is not one standard ground resistance threshold that is recognized by all agencies. However, the NFPA and IEEE have recommended a ground resistance value of 5.0 ohms or less.
How can we improve poor earthing?
Basic Methods to Reduce the Resistance to the Ground
- Increase the Rod Thickness. Let’s assume we bury a standard ground rod with L = 300 cm, and d = 1.270 cm, in soil with ρ = 10,000 Ω·cm.
- Increase the Rod’s Length.
- Use of Multiple Rods.
- Treat the Soil to Decrease its Resistivity.
Why Bentonite is used in earthing?
Bentonite is a sodium activated montmorillonite which, when mixed with water, swells to many times its dry volume. This enables moisture to be absorbed from the surrounding soil (e.g. rainfall), solving any soil to earth rod contact problems.