On 16 Sep 2006 23:41:55 -0700, "BobK207" wrote:



If a small diameter ground rod (1/2" or 5/8") doesn't give the 25 ohms
(or less) to ground.....would a larger (3/4" or 1") diameter rod in the
same soil do better?

Is the soil the culprit or the soil / rod contact resistance? The
larger diameter rod contacts more soil..better grounding behavior?

cheers
Bob

This is just opinion; I don't have facts to back it up...but..

The two are related. You have two resistors in series, one
represents the rod to ground resistance, the other ground resistance
back to the utility ground. The same factors that increase one (poor
soil conductance) influence the other. But I'm SWAGing that the ground
resistance back to the utility dominates most of the time. If you're
right on the hairy edge, a bigger rod might help enough. But I'd be
inclined to go with a longer rod, not larger diameter, because it
might get you to better soil, where a larger diameter rod just makes
more contact with the same (lousy) soil.

As I said, just conjecture on my part...

Paul