measure resistance of grounding system

[tom baker]

Thanks for all the replys. I called the manufacture there reply was the better the grounding system the better , of course. My objective was to provide the cleanest power possible for the cost, dairies have more and more electronics every year latest is VFD 15-20 HP THE TVSS i PURCHASED SHOULD CLAMP TO 800V IF my understanding is correct,anything above that goes to ground thus my orignal question to test thanks agin this is my first trip to this site.

TVSSs do not divert surges to ground. Its widely misunderstood in the industry that they do.

 

[brian john]

While the clamp on can and does work there are issues with their use. If you have downstream grounds (neutral ground bonds downstream from the main service or SDS) you will get low/false readings. Some meters account for this and give an error message. As about 90+% of the electricial distribution systems we investigate, service or test have downstream grounds we prefer to use the three point FOP test method. The 3-point test also has it's draw backs, for one the electrode under under test has to be isolated.