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#94027 07/01/05 12:51 PM
Joined: Jan 2004
Posts: 1,507
Well this one will get you thinking [Linked Image]

Contractor uses an "Acorn" clamp- the type of clamp you use to terminate a GEC on a ground rod, to secure the #8 solid to the rebar of a pool. So the question is: can he fold the #8 over and not cut it and slip it in between the rebar and the clamp? Is this considered 2 wires now? We all agree that this type of clamp is only Listed for one wire. Secondly, is this clamp suitable for rebar? I have been approving this type of connection for years and now it appears I could be in error.

As the attorney said-"What say you?"

George Little
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#94028 07/01/05 07:54 PM
Joined: Jan 2001
Posts: 1,044
Tom Offline
Clamps approved for direct burial are also approved for concrete encasement (see the UL White Book "KDER"). i don't see anything in the UL listing that would prohibit the use of an acorn clamp to rebar if the clamp was correctly sized.

IMO, bending the wire over is going to have to be a judgement call on your part, though I don't see why this would need to be done.

A question for you. If someone hammered in a piece of 5/8" rebar as a grounding electrode, would you accept this per 250.52(5)(b)? If you did accept this, would you require a special "rebar" clamp or would an acorn do the job?

Personally, unless someone can come up with something really compelling, I'd continue to accept the acorn clamp that is listed & marked for direct burial. I think your years of experiance in this area are correct. I'm also sure that if I'm wrong, someone will kindly point out the error of my ways.


Few things are harder to put up with than the annoyance of a good example.
#94029 07/01/05 11:04 PM
Joined: Jul 2004
Posts: 9,788
Likes: 14
George I vote it is still one wire. The reason we worry about multiple wires in a terminal not rated for it, is one may be getting all the pressure and the other still loose.

Greg Fretwell
#94030 07/02/05 08:42 AM
Joined: Mar 2004
Posts: 16
JG Offline
It is not allowed in NM: Cu to FE in direct contact: Art 110

#94031 07/02/05 01:37 PM
Joined: Jan 2004
Posts: 1,507
JG- Would you mind explaining your abbreviations? And Code reference beyond the Article number? Thanks.

NM = New Mexico?
Cu = Copper?
FE = ?
Art 110 = Maybe 110.14?

George Little
#94032 07/02/05 08:43 PM
Joined: Jul 2004
Posts: 9,788
Likes: 14
Grorge I would not like a #5 rebar ground rod but I think I would have to just talk them out of it or 90-4 them.
250.52(A)(5) doesn't seem to prohibit it.

(b) Electrodes of rods of iron or steel shall be at least 15.87 mm (5/8 in.) in diameter. Stainless steel rods less than 16 mm (5/8 in.) in diameter, nonferrous rods, or their equivalent shall be listed and shall not be less than 13 mm (1/2 in.) in diameter.

There are lots of acorns listed for rebar

Greg Fretwell

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