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

[Mike McCarthy]

Eevry tower I order now has a 6 x 6 tab butt welded to the base plate for
attaching exothermic welds or other tasks which requires some form of heat
stress to attch something.  If there isn't one and the base plate isn't
large enough for the mold, I'll usually have a plate butt welded on to the
base plate or leg flange outer side surface away from the legs. The base
plate will take a LOT of heat before it would become deformed. Base plates
are also never in a tension mode and not deform due to compression.

I will NEVER heat attach anything to a member (leg, diagonal, girt)
without an opinion by the manufacturer or competent structural consultant.
The last one I NEEDED to do was VERY carefully done by alternating "tack"
welds between the various horizontal members so as to not excessively heat
them.  Usually about 1/2" at a time going through a dozen welds in
sequence.

That said, CBS had no choice but to weld direct to their tower here.  They
needed to strenghten most of the members in the top 50ft. to support a 2nd
B/U antenna. As I recall, it was done VERY carefully and across many
members so as to not heat them. It took a LONG time to perform the work
and was quite costly.

MM

> 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