[Cu-wireless] Re: Cu-wireless digest, Vol 1 #177 - 1 msg

[Peter Folk]

Urbana and Champaign both use the National Electric Code as the basis
of their building safety code.  The NEC doesn't talk about how to pro-
tect yourself from lightning, and nothing is required by law, tho your
insurance might be lower if you have one installed.  Lighning protection
systems should be installed according to NFPA standard 780, available
from www.nfpa.org for $30. 

That said, the NEC and Champaign electrical inspector (I haven't talked
with Urbana yet) do care how you do grounding.  Take my advice only at
your own risk, but my reading and talking with the Inspector came up with
the following guidelines: 

1) If you ground, you must bond all your grounds together.
2) No ground wire can be longer than 20' (this seems hard to do,
but is the rule).
3) No two ground plates (or rods) can be closer than 6' together,
or closer than 6' to another grounding system. 

If you're worried about lightning, don't ground only to the house
wiring, as that can lead to fires; you should run a separate #6 or
larger copper conductor from the antenna site to ground. 

If anybody knows more about this they should speak up now; the above
is just based on my own studyin', askin', and figurin'. 

Pete 

> Date: Sun, 28 Jul 2002 21:19:20 -0500
> From: David Young <dyoung at ojctech.com>
> To: wireless at lists.bawug.org
> Reply-To: dyoung at pobox.com
> Subject: [Cu-wireless] lightning protection? 
> 
> 
> I am going to attach a pole to my chimney and mount on the pole both
> a computer and an omni antenna. A short piece of LMR-400 will link the
> computer and the antenna. Outdoor-rated Cat5 will carry power and data
> from inside my house to the radio. 
> 
> How do I protect this setup from lightning? I want to protect my equipment
> and my landlord's house from damage, indoors and out. 
> 
> Is it likely that the chimney has a good ground? I see no lightning rod
> from the ground. If not, should I bring a ground conductor down to earth?
> Down to the nearest ground? (Presumably there is a good ground where
> the power lines enter the house.) 
> 
> I presume a surge suppressor belongs on the Cat5. Inside or outside the
> house? As near the computer enclosure or as far from it as possible? 
> 
> Also, I presume a suppressor belongs between the antenna and the computer
> enclosure? 
> 
> Dave