Correcting the misconceptions of ground testing
BY JEFF JOWETT, Megger
Ground resistance testing is sometimes described as an “art”, and indeed something can be said for that description. Familiarity with the basic issues and common problems, however, can take much of the “art” out of it and put your testing program on a firm, repeatable basis.
BEGIN WITH THE CORRECT INSTRUMENTATION
Use a dedicated ground tester, an instrument that has separate current and potential circuits that the operator can manipulate at will by placing test probes in the soil. This is the critical difference between a ground tester and other common testers with a resistance range.
When testing a discrete item, like a motor or circuit, two test leads are usually sufficient. The small amount of resistance that they contribute may be negligible, or it can be nulled out or measured and treated as a tare.Read the full article in our digital magazine