[BC] thanks to the list re: grounding system advice.

[Broadcast List USER]

Drilling holes in a tower member is a LARGE move away from goodness.

You are weakening the member, and unless the tower manufacturer or a  
mechanical signs off on it, it is just stupid.

The holes also break the zinc seal, so corrosion WILL become a problem.

If you stay on top of it, grinding off zinc galvanizing for a  
connection, then sealing it is OK, but for the long term health of the  
tower it isn't a good idea.  The reason is that some day, you will be  
gone, and the next guy may not be as good as you at keeping up on the  
problem.  Yes, it is a problem that you have to keep up on or there  
WILL be a failure.

Stainless puts three (or more) rods on the base, under the legs as  
places to attach grounding.  Even if those totally fail, there is no  
structural damage to the tower.

Clamping galvanized steel cable to the tower is OK, and won't cause  
issues.  Those steel cables can be cadwelded to the ground rods/ 
system.  The key here is to keep the dissimilar metals' connections to  
places where they can be easily replaced.  Tower members, especially  
legs, at the bottom of the tower are not easily replaced.

--chip

PS.  I once caught a tower guy drilling a member on a tower I owned.   
I made the tower company pay for a study.  They did.  They ended up  
replacing the member at a considerable cost.  I'm sure those guys  
never drilled another tower member without written directions to do it.

--chip

On Apr 26, 2010, at 9:00 AM, broadcast-request at radiolists.net wrote:

> Message: 5
> From: Ron Youvan <ka4inm at tampabay.rr.com>
> [...]
> They recommend and we have been using compression connectors  
> designed for lighting installations
> and bolt on lugs.  They crimp a two bolt lug on the cable end and  
> drill and tap two holes in the
> tower member, a gusset at the bottom flange) remove the galvanizing  
> with a grinding wheel and apply
> Anti-Ox and bolt the lug to the steel.
> [...]
> Ron KA4INM