My Ufer ground megged at 4 ohms. No ground rods.
73, Mike NF4L
> On Aug 8, 2015, at 11:02 AM, Paul Christensen <w9ac@arrl.net> wrote:
>
>> "Then there is the "default" - 10 ohms - maybe one ground rod and 18 gauge
> wire? Hilarious!
>
> Not too hilarious on the day we were driving 24 ft. rods with a hammer drill
> just to get under 10-ohms in the sandy soil of North Florida. Repeated 4
> times to get below that target. Two 8. ft rods spaced 16 ft. and connected
> together with #2 copper gets you to maybe 50-60 ohms here.
>
> I can see why the G spec also requires 10-ft rods. We saw an asymptotic
> effect when adding more and more 8 ft. rods. The 24 ft rods allowed us to
> reach the goal line. We went from about 30 ohms with many 8 ft. rods to 10
> ohms with just one 24 ft. rod. The end result was about 5 ohms as measured
> with a clamp-on earth tester with the four 24 ft. rods placed at the shack
> EGB, each of the two tower bases, and in between each tower.
>
> That said, I do agree there's often a lot of "spec polishing" in the trades.
> For example, why is that a 3/4" PVC emergency drain pan line for my hot
> water heater was fine in 2001, but then local code increased it to 1" the
> next time it was replaced? Then code required 1-1/4 just recently with the
> last heater change. Just how hard is it to figure how big is a "big enough"
> line for a drain pan? In 4-5 years, will that change to 1-1/2"?
>
> Paul, W9AC
>
>
>
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