grounding grid

[hawkeye23]

When testing a industrial site's ground grid is megging it the only test thats used? What test are used to check its integraty ?

 

[ptonsparky]

Megging is used for high resistance testing, not low.

 

[edavis2293]

Null Meter

Null Meter

When testing grounding resistance we use a null meter. The one I see most is made by Biddle. There are two (2) additional electrodes used but only about 12" long. Follow the directions that come with it, very easy to operate. As many times as I have used these, 25 ohms is not even close and a second electrode is required.

 

[brian john]

There is a misconception as I think Megger use to call there 3-point tester an EARTH MEGGER.

There are several good links for Earth/Ground Resistance Testing.Here is a good start.

http://www.aemc.com/techinfo/html/Tech-GroundTesters.asp

 

[zog]

When testing a industrial site's ground grid is megging it the only test thats used? What test are used to check its integraty ?

As mentioned you don't use a megger, you need to do a 3 point fall of potential test at several different distances from the grid to verify your measurements are accurate (Looking for a plateau). You also want to check all connections using a microhmeter. Your best bet is to contact a testing company that has the equipment, training, and procedures to perform this test.

 

[don_resqcapt19]

What are you trying to test? Are you really looking for a ground resistance test or are you looking to prove that every thing is bonded together?

 

[hawkeye23]

There appears to be a lot of unsettling ground, dips and holes just concerned that there is not a problem with the underground cables.