The earthing compounds are a combination of minerals used to lower the soil resistivity while holding on to the moisture present in the soil for a long time to ease the soil’s conductivity. Earthing compounds are also used as fillers that shield the ground electrode primarily to lower the earth’s resistivity. These compounds are also called conductive backfills, ground enhancement backfills, earth-bonding substances, earth-bonding components, and conductive concrete. The use of earthing compounds is very common everywhere and it has changed a lot in the last few years. In this comprehensive guide, we will talk about the necessity of earthing compounds for electrical earthing.
What is Needed for Earthing Compound?
Few things are considered best for a perfect earthing compound but these compounds have to be harmonious with the grounding electrode materials, which are environment friendly. These compounds should not react to electrode materials, if this happens the result would be unsafe earthing. Furthermore, the earthing compound should not contain toxic substances or it will be mixed in the surrounding soil. These earthing compounds should go through the following tests:
Sulphar Test: Too much Sulphar in the earthing material can cause corrosion of earth electrodes. If the measured value is not more than 2%, the earthing compound passes the test very easily.
Leaching Test: This particular test ensures the backfill compound is chemically tuned and does not leach, as it has to stay in the same position for a long time. The purpose of doing a leach test is to determine how much iron, copper, zinc, nickel, cadmium, cobalt, and lead are present in the compound.
Resistivity Test: The resistivity test is necessary and it should be done using the Wenner four-electrode method. The testing gadgetry for this particular test includes an earth resistance meter and, a four-electrode soil box. After measuring, the value should be higher than the value mentioned on the package of the product.
This particular test is very important because these compounds have to be stationary both chemically and physically to prevent corrosion of the electrode. To determine the corrosiveness the polarization resistance technique is used.
Make sure these tests are done on the earthing compound you are purchasing or the results would be poor earthing.
The Best Earthing Compound for Electrical Earthing
Bentonite: This one is moisture-preserving clay, which is utilized as an earthing compound. The compound we have here consists of Morolite. It is also present as sodium bentonite or calcium bentonite. This compound can store some amount of impurities and thus ensure no heavy corrosion to the earth electrodes. Because its resistivity is very low in wet conditions, therefore it can be utilized as a backfill in the earth pit after mixing this water. The Bentonite stays unaffected for a long duration but eventually is leached if contamination in the soil catches up to it. Nevertheless, in the long earthing material list this one serves as a solid earthing compound.
Charcoal & salt can also be a good earthing compound but eventually, it is drained out. It can be said for the Maronite. It is mostly used in industrial, commercial, and residential buildings for effective earthing.