Testing Earth Ground

Thread Starter

AutoNub

Joined Oct 14, 2011
44
If I have an 8 ft deep ground rod and want to test its effectiveness, can I simply measure the resistance between the local power outlet's ground and the earth ground in question? Will this give me any useful data? I measure about 6.5 Ohms between the utility ground and the isolated earth ground. I'm thinking the resistance between the two grounds should be (0+(the accumulative resistance (as determined by its resistivity or resistance per unit length) of the conductive material between the point of contact with my probe and the point of dissipation to ground)). Is this accurate? Thanks for the insights!
 

thatoneguy

Joined Feb 19, 2009
6,359
<10Ω is good. Low enough resistance that no dangerous voltage level can "build up" on your ground without being dissipated.

Resistance will go down if it rains or freezes.

Is your local ground for an antenna, or some other purpose?
 

Lundwall_Paul

Joined Oct 18, 2011
236
It is not accurate. I have always used ground testers. Perhaps you can find an electrician who has one and have him measure it. Check out on line the Fluke 1625. Checking a ground rod cannot be checked with an ohm meter.
 

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