For a few ohms less
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Earthing is often not given as much attention as the installation of good wires, proper power plugs and even electrical safety. The consequences could be devastating sometimes.
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A word of caution: Bad earthing can damage your precious home theatre.
In July this year, officials of the Kerala State Electricity Board (KSEB) were carrying out routine repair work at a transformer in the Vattiyoorkkavu area. All of a sudden there was a power surge in the lines that feed nearby housing colonies. In the lightning-fast onrush of power almost all electrical equipment in the houses in one colony went kaput. Angry residents surrounded KSEB officials wanting to what went wrong and why.
The faults of the KSEB, apart one thing that could have prevented a burn-out of costly equipment, was a good ‘earth’ of the wiring systems of the houses; something that is often not given as much attention as the installation of good wires, proper power plugs and even electrical safety devices. This is particularly true in the case of independent houses.
Apartment complexes are much less prone to earthing problems as various inspections are mandated by law before the office of the chief electrical inspector clears the wiring system of that building complex.
What is earthing?
So what is ‘earthing’ all about? A house’s electrical pathways are connected to the earth with a rod inserted inside a pit filled with salt, charcoal and water right? Not entirely so.
For one thing dry salt is a very poor conductor of electricity. It has to be kept wet all the time. In practice, this is never done by any house owner. Fact is, not many house owners would be able to locate the ‘earthing point’ of their house.
Air, as any scientist would tell you, is one tough insulator; has to be for the safety of life of earth. To ‘break’ one millimetre of air, you need one kilovolt of electricity. So what if an air pocket forms inside the pit where the earthing rod is inserted? Moreover, the use of iron rods without adequate copper plating also poses a hurdle in the effective draining off of electricity.
“Many people mistakenly think that it is the onrush of power into a house’s electrical system that kills electrical equipment,” points out B. Murali Kumar, an electrical engineer and the regional manager of a firm that sells a special chemical ‘earthing’ compound of French-make. “Almost all electrical surges peak in about eight micro-seconds. This is too fast for almost all electrical equipments to register. The real damage is done by the outflow of current as the voltage stabilises. The time taken by a power surge to normalise inside a house’s electrical system depends on the quality of the earthing.” Mr. Murali compares earthing to a good plumbing system; one that offers the least resistance to the draining off of water. Likewise a house’s earthing has to offer the least resistance to the outflow of excess electricity.
For this the earth’s resistance has to be brought down to 1 ohm or even below irrespective of seasonal, atmospheric or soil variations. Mr. Murali points out that even without using any branded products it is possible for a person to ensure that the earthing in his house is stable.
A precaution
“When you are laying the earthing, increase the presence of salt in the soil by at least 10 per cent over the quantity normally used. Care should be taken to ensure that the salts are equally distributed in the pit dug for the purpose. The house owner should also ensure that there are no air bubbles inside the pit.
Most important, there should always be moisture inside the pit so that the mixture around the conductor rod is always in a jelly state. And yes, the conductor should be a copper or a copper-plated rod,” he explains.
The French-made earthing compound that Mr. Murali markets is said to contain, among other things, dispersion chemicals to ensure that salt is evenly distributed in the soil, expansion chemicals – sodium, potassium and aluminium silicates mined from volcanic eruptions—that expand 18 to 20 times when in touch with the ground ensuring the absence of air pockets, diffusion chemicals that create conductive roots into the soil with the passage of time, hygroscopic chemicals that absorb water from the surrounding soil to keep the earthing pit in a permanently moist condition and other special chemicals that keep the earthing mixture in a jelly form. Mr. Murali claims that this compound – named TEREC –can keep an earth pit maintenance-free for 15 years.
Mr. Murali’s firm also markets a lighting conductor system – a system that is said to be capable of actively attracting lighting to itself – that provides protection in a 110 meter radius. He can be contacted on phone 9895401102.
G. MAHADEVAN
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