Towertalk
[Top] [All Lists]

Re: [TowerTalk] Cadweld vs clamps

To: towertalk@contesting.com
Subject: Re: [TowerTalk] Cadweld vs clamps
From: Jim Lux <jimlux@earthlink.net>
Date: Thu, 23 Oct 2014 15:15:21 -0700
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
On 10/23/14, 11:34 AM, Bill Turner wrote:
------------ ORIGINAL MESSAGE ------------(may be snipped)

On Wed, 22 Oct 2014 21:19:50 -0700, David Gilbert wrote:


What is it you want to know that hasn't already been explained for
you?   You either buy the technical explanations or you don't, and if
you don't accept them, why would you expect any other comment to change
your mind?  Anything else is just going to be conjecture.

Dave   AB7E

REPLY:

Good question. The answer is that if Cadweld is so superior, why is in
not mandatory in the NEC? Why are ground clamps allowed at all?  They
are a very conservative organization and surely would err on the side
of safety.



Listed compression fittings are allowed
Wedge locked fittings are allowed
(generically, "connectors listed as grounding and bonding equipment")

Clamps are allowed, with periodic inspection to insure that they are still tight.

250.68 A All mechanical elements used to terminate a grounding electrode conductor or bonding jumper to a grounding electrode shall be accessible. Exception No. 1: An encased or buried connection to a concrete-encased, driven, or buried grounding electrode shall not be required to be accessible.

Exception No. 2: Exothermic or irreversible compression connections used at terminations, together with the mechanical means used to attach such terminations to fireproofed structural metal whether or not the mechanical means is reversible, shall not be required to be accessible.

250.70 Methods of Grounding and Bonding Conductor Connection to Electrodes.
The grounding or bonding conductor shall be connected to the grounding electrode by exothermic welding, listed lugs, listed pressure connectors, listed clamps, or other listed means. Connections depending on solder shall not be used. Ground clamps shall be listed for the materials of the grounding electrode and the grounding electrode conductor and, where used on pipe, rod, or other buried electrodes, shall also be listed for direct soil burial or concrete encasement. Not more than one conductor shall be connected to the grounding electrode by a single clamp or fitting unless the clamp or fitting is listed for multiple conductors. One of the following methods shall be used:

A pipe fitting, pipe plug, or other approved device screwed into a pipe or pipe fitting

A listed bolted clamp of cast bronze or brass, or plain or malleable iron

For indoor communications purposes only, a listed sheet metal strap-type ground clamp having a rigid metal base that seats on the electrode and having a strap of such material and dimensions that it is not likely to stretch during or after installation

    An equally substantial approved means



I don't believe clamps are allowed in a buried application (you'd need inspection wells, and then the clamp isn't actually buried).
_______________________________________________



_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk

<Prev in Thread] Current Thread [Next in Thread>