[BC] AM Grounding and Bonding

[Robert Meuser]

Mike:

One caution, you should always work in conjunction with the manufacturer 
before welding to any structural member whether it be pilings of the 
tower legs themselves. You can put yourself in a situation where if 
something happens to the tower the manufacturer has an out.  I would 
spec the buss bar or any other welded attachment as part of the structure.

R




Mike McCarthy wrote:

> Hi Andy,
>
> I would exothermally weld 4/0 copper wire and bring one or two leads 
> up to the base pier for bonding to the RF ground.  The pilings do 
> little/nothing for the AM signal, but will provide one great lighting 
> ground system. I would also install conventional ground rods in 
> addition to the pilings so that you are not relying on structural 
> steel for the lightning ground.
>
> As for the bridging the gap to steel for strap...simple. I 
> exothermally weld a piece of copper bus-bar to the steel, then sliver 
> solder a piece of strap to the bus bar.  In some cases, you will need 
> to add a tab to the base plate (butt welded to our circumference 
> surface of the plate) for the  exothermic weld.
>
> If you have Brian from NorthStar there, ask him what we did at the 
> project he assisted me here.
>
> MM
>
>
>
> At 09:32 AM 4/9/2007 -0700, Andrew Skotdal wrote:
>
>> We're driving steel pipe piles 55 feet down to support some new AM
>> self-supporting radiators.
>>
>>
>>
>> 1.      If there are nine piles below the foundation, do you ground to
>> one of them or to all of them?
>> 2.      What type of attachment from your ground system should be bonded
>> to the pile(s)?
>> 3.      Do you use 6 inch strap?  If so, how do you avoid electrolysis
>> between the steel pipe and copper strap, and how do you avoid the
>> calcium in the concrete eating your copper strap?  (Is the lack of air
>> enough so you can run the copper through the cement without protecting
>> it?)
>> 4.      Or, do you use some kind of lesser coated copper wire similar to
>> a heavy gauge wire you might use in connecting studios to your frame
>> room?
>>