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Re: [TowerTalk] Cadweld vs clamps

To: towertalk@contesting.com
Subject: Re: [TowerTalk] Cadweld vs clamps
From: Jim Lux <jimlux@earthlink.net>
Date: Sun, 26 Oct 2014 10:22:39 -0700
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On 10/26/14, 9:09 AM, N3AE wrote:
The question of tying grounds together seems to come up often. I started a 
thread a few weeks back with a question on tower grounding which was hijacked 
into a spirited discussion on ground-to-neutral connections in outbuilding load 
panels.

Guess I'll know the "official" position shortly. Just called to schedule a 
final inspection for my tower project only to learn I had to pull an electrical permit 
too. Previously I was told I did not need electrical. Local officials seem to make it up 
as it goes along. At my QTH however, only a Master Electrician licensed in the county can 
pull an electrical permit, so it seems I must now hire someone to ground my tower, deal 
with bonding, coax suppressors, etc to requirements in Article 810 of the 2011 NEC. The 
challenge will be finding a local licensed electrician who is familiar with these 
requirements as most work around here is residential and small business/light industrial.

To jump into the current discussion, I believe I have to follow Figure 15 from 
the link below. We can argue the physics like distance and voltage differential 
due to propagation time, but at the end of the day it's just the inspector's 
opinion that matters.

I'll provide a summary later of how it goes.

http://www.reeve.com/Documents/Articles%20Papers/AntennaSystemGroundingRequirements_Reeve.pdf

Shawn - N3AE



Reeve's writeup is very good, and his comments on the handbook chapter (of which I am the author/editor for the most part) are well taken.

As he points out, the NEC is sort of a hodgepodge that has evolved over the years, and modern versions are MUCH more consistent and use better terminology than older versions (2014 is the latest edition). Be aware that your local jurisdiction may not use the latest version (mine doesn't). I think for the most part that compliance with the latest version won't cause problems with an inspector looking for compliance with an older version (and in any case, it's the inspector's word that is final)




With respect to guidance to amateur radio licensees, either in the handbook or online in forums such as this, there is a fine line to be walked between "strictly according to code" and "what people are actually likely to do".

A good example is the code requirement for "listed antenna discharge units", of which there are none suitable for amateur HF antenna use (at least that I've found.)

Another is that I doubt that most wire antennas meet the code requirements of hard drawn copper or copper clad steel of the gauges required in the code. We can hand wave a bit and say that wire antennas made with AWG20 wire are temporary in nature, and may fall under one of the exceptions for such things; nobody would expect a AWG 20 magnet wire antenna to stay up for very long.



On local codes vs NEC..
Here's mine:
That certain Code designated as the “California Electrical Code,” 2013 Edition, based upon the 2011 National Electrical Code, including Annex C and D, published by the National Fire Protection Association, at least one (1) copy of which is on file in the Office of the Building Official for public record and inspection, is hereby adopted by reference and made a part of this chapter as though set forth in this chapter in full, subject, however, to the amendments, additions and deletions set forth in this chapter, and said Code and provisions shall be known as the Electrical Wiring Code for the City.

and then goes on later...
...served by adding to and amending the California Electrical Code, and, therefore, said California Electrical Code, 2013 Edition, is hereby amended to read as follows...


Among which is this
Article 90.4. Enforcement.
   (A)   Used Electrical Equipment.
Unless otherwise approved by the Building Official, all electrical equipment installed in the City of Thousand Oaks shall be new and shall be listed by a recognized testing laboratory. Used equipment may be installed when sufficient documentation has been received and approved by the Building Official. The documentation shall consist of tests by a recognized testing laboratory sufficient enough to warrant and certify the equipment as safe for the intended use.

-> a strict reading of this means that you can't install that used electrically actuated telescoping tower, or for that matter, perhaps even a used ham rig.

-> This is where having a non-confrontational agreeable attitude with the local authorities helps. Especially if you have someone looking to stop your project who is looking for this kind of stuff. If the local inspector (aka Building Official) signs off, it's good.

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