[BC] AM Grounding and Bonding

[Cowboy]

On Monday 09 April 2007 12:32 pm, 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?

 All of them, if possible. Preferably a star configuration.

> 2.	What type of attachment from your ground system should be bonded
> to the pile(s)?  

 Since this is essentially a lightning ground, a #6 copper wire would be fine,
 and run that to the strap below the base insulators as directly as possible.

> 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?)

 Again, #6 insulated.
 I'd either cad-weld it, have a bonding stub MIG welded to the piling ( with manufacturer's
 blessing - it's a structural thing ) or clamp the copper over a sheet of stainless between
 the copper and the steel.
 Silver-bronze brazing will work fine as well, to the bonding stub as long as it's CLEAN !
 Finally, coat the thing liberally with roofing tar or some such to keep water and dirt
 away from direct contact with the wire and the connection point.
 Jason knows, and Brian cares. Something very similar to the way we did the tower 
 feeds in Detroit.
 Either can call me if there's a question.

> 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?

 Very similar, yes, but I'd use larger. #6 probably.

-- 
Cowboy