Home & Garden
You would need an 'Earth Resistance Tester' (often called a Megger) to begin this process and then additional rods + other items. Best to find a local electrician with this kit since he would probably complete the test quite quickly and at least you would have a 'proper' idea from someone who knows what they are doing and can issue some paperwork at the conclusion.
In very simple terms, and as i understand it, the earthing system is designed to trigger protective systems in the event of a fault both in the house and at the transformer in the street. Both react within specific limits.
In the event of a fault, say, in a washing machine, when the fault reaches the consumers earth rod, it passes along the ground until it reaches the EDF spike at the transformer (which may be some distance away) when the current returns to the transformer where it started from. If the fault current exceeds 500 milliamp then both RCD's begin to trip (the consumer one and at the transformer) but as the EDF one is of a higher setting for earth faults as well as a 40 millisecond time delay, the consumer's RCD trips first, thus clearing the fault. The whole process takes takes about 10 to 20 milliseconds. If, for some reason, the consumers RCD didn't clear the fault, then the EDF RCD would trip after the 40 millisecond delay.
Because of its significance in the safety cycle, the requirement is to have an earthing system with a maximum resistance of 100 ohms. To test, this requires an earth testing instrument which passes an alternating current of about 120 Hz between several poles driven into the ground and is a somewhat specialised operation. It is to prove the resistance of your system and to ensure safety electrical safety is maintained by verifying the soil meets the required parameters to, as it were, act as an effective communicator in a timely fashion with the transformer to chop the power if all else fails.
In my days at work it was called the PELIT, Phase Earth Loop Impedance Test and was obligatory for all new installations test certificates. Megger is the maker of a test instrument but they also make other test instruments that will not do this test, Fluke is another well known maker.
See http://www.weschler.com/_upload/sitepdfs/techref/gettingdowntoearth.pdf for a guide.
Become a Member
Registering with AngloINFO is quick and simple and gives you a lot of additional opportunities to benefit from AngloINFO's many services. It's also completely free of charge.Read More...
Forex Cross Rates