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# Grounding rod depth?

## Grounding rod depth?

#1
05-28-03, 08:48 PM
msr
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Grounding rod depth?

I live in Austin Texas. I am hitting rock at 6". How the heck am I supposed to sink this thing 8'?

#2
05-29-03, 03:03 AM
lestrician
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Put it in at an angle.

#3
05-29-03, 04:28 AM
bungalow jeff
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You can lay copper rods along the top of rock, but with only 6" cover, you may need a different solution. Is there rebar in the foundation? If so, chip out to expose a bar, ground to that and patch.

#4
05-30-03, 07:10 AM
Member
Join Date: Feb 2001
Location: sw VA
Posts: 3,022
Are you sure you are not hitting the footer next to the house??

At times, I've had to come out from the house as much as 14 to eighteen inches to get away from the footer.

fred

#5
05-30-03, 09:44 AM
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Join Date: Sep 2000
Location: Fayetteville, NY, USA
Posts: 969
You may drive a ground rod at a maximum of 45 degrees from vertical. Alternately, you may use a grounding plate. This plate shall expose no less than 2 square feet of surface to exposed soil (12" x 12" = 1 square foot per side = 2 square feet.) Plates of ferrous metal (iron, steel) must be 1/4" thick. Plates of non-ferrous metal (copper, stainless steel) must be .06" thick. Plate must be buried at a minimum of 30" below finished grade. Reference: NEC 250.52(A)(6). Hope that helps.

Juice

#6
05-30-03, 09:03 PM
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Join Date: May 2002
Location: Seattle
Posts: 214
Is there rebar in the foundation? If so, chip out to expose a bar, ground to that and patch.
In order to use the "ufer" ground method, you have to prove that the rebar is, or is connected to at least 20 linear feet of buried rebar.
250.52(a)(3)

#7
05-30-03, 10:30 PM
bungalow jeff
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Originally posted by marcerrin

In order to use the "ufer" ground method, you have to prove that the rebar is, or is connected to at least 20 linear feet of buried rebar.
250.52(a)(3)
Good point. Connecting to a horizontal bar on a wall over 20' long should provide this, but there would be no way to be sure, short of screwing up the foundation.

Many homes, particularly old ones, have no rebar to speak of anyway, so the plates may be the way to go, however something would have to be done to increase the ground cover from 6" to 30". Maybe a short retaining wall. Any takers on a minimum area MSR should increase the ground cover?

#8
05-31-03, 05:17 PM
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Join Date: Sep 2002
Location: welland ontario
Posts: 8,059
I would call the AHJ and ask for an interpertation.