[TowerTalk] Ufer gnds/foundations

[W7CE]

>
> I'm not a student of Ufer grounds.  However, I HAVE engineered some
> large towers...including a 500' self supporter.  Everyting I've
> read says...provide a low impedance path AROUND the foundation,
> not through it.
>
> Think about it...1 million amperes is going to vaporize just about
> anything you put down there.  I've seen 8" copper strap, 1/16" thick
> simply dissapear.  If it's inside the concrete, the expanding vapor
> will cause cracking and structural failure.
>
> My sense of the Ufer ground was that it was intended to reduce
> corrosive currents, and improve conductivity, not to handle peak
> lightning strikes.  Perhaps I'm wrong.  I'm sure the assembled
> expertise here can correct me.
>

I'm certainly no expert either.  That's why I'm asking the questions.  My 
research pointed to Ufer grounds for towers as a good solution.  Ufer 
proponets claim that exploding concrete is a myth.  I got the impression 
that most modern communication facilities use Ufer grounds for lightning 
protection.

I am curious about something.  If lightning will vaporize an 8" x 1/16" 
strap, why even bother?  That tells me that #2 solid copper wire should 
vaporize in direct strike also, yet direct hits happen all the time and the 
wire and equipment survive.

Regardless of which grounding system I use, I am thinking that deeper is 
better, especially since my soil is very dry for the first 7-8 feet.  Here's 
an interesting link that I found last night on the subject of ground rod 
depth:

http://www.cpccorp.com/deep.htm

73,
Clay  W7CE