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).
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