This keep coming up from time to time and being a retired electrician the
NEC has been updated in the late 90's. There is requirement for a ring
ground and it's all laid out in code. The information is ready available
from lots of sources and all hams with or installing a tower should follow
code. Besides the house you save is yours. I helped a friend of mine with
his electrical system after he took a super hit and if he had been in chair
when it struck he would had been killed. On inspection I found over the
years the tower had corroded the connection's away at it ground rods. It
came in on the coax's and to find it pass to ground return by the electrical
line's. When I installed both of my towers under permit it had to pass
electrical inspections. Also just a point of information either use cad
welds or proper mechanical approved clamps in your grounding system. 73
Gene AA4VX
-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of Al
Kozakiewicz
Sent: Sunday, December 30, 2012 1:10 PM
To: Patrick Greenlee; towertalk
Subject: Re: [TowerTalk] Fwd: Re: Earthing a tower
Have your friend Google "Ufer ground"
Al
AB2ZY
-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of
Patrick Greenlee
Sent: Sunday, December 30, 2012 12:17 PM
To: towertalk
Subject: Re: [TowerTalk] Fwd: Re: Earthing a tower
I have a friend who is a ham and is EE with 30+ years of antenna design
experience. He tells me emphatically, "concrete is not a good conductor."
Given this, I'd be trying to not depend on concrete as part of a grounding
system. Rebar installed correctly in steel reinforced concrete is probably
at least 2 inches under the surface of the concrete on any side, top, or
bottom. Weld plates installed when the concrete was wet (to give you
something to anchor to) or bolts or other components set into the concrete
are typically NOT in contact with the rebar cage inside the concrete (which
is not a good conductor anyway.) So again, it is better to not rely on the
concrete to conduct.
73 Patrick AF5CK
-----Original Message-----
From: Jim Lux
Sent: Wednesday, December 26, 2012 8:58 PM
To: towertalk
Subject: [TowerTalk] Fwd: Re: Earthing a tower
-------- Original Message --------
Subject: Re: [TowerTalk] Earthing a tower
Date: Wed, 26 Dec 2012 17:28:43 -0800
From: Jim Lux <jimlux@earthlink.net>
To: Jim <zl2bmh@xtra.co.nz>
On 12/26/12 3:14 PM, Jim wrote:
> Hello.
>
> I hope I have sent this correctly, as it's my first post.
>
> Is it necessary to earth a tower?
Yes..
If your tower is securely bolted to a concrete base with bolts and there's a
decent amount of rebar in the base, it's probably pretty well
grounded/earthed.
The concern is whether the bolts are in close contact with the concrete with
no tiny crack for water to get in and corrode the steel, or for the water to
create steam in the event of a lightning stroke. Typically, this is assured
by keeping the top of the concrete above grade and sloped so that water
doesn't just sit on it.
If it's just sitting on the bare soil, you might want to do some more
grounding.
A bigger issue is whether the coax shields are bonded at the bottom of the
tower, or where they come into your house, etc.
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