UFER tie-in on retrofit concrete work

[swei]

New service for a 70-year old reinforced concrete building. New service elevator required cutting/excavating the basement floor for the reinforced concrete pit. Plan to add a supplemental GEC (rod) at the bottom of pit (one of the few places we can get down to the soil on this property.) Normally I would exothermic weld to a piece of rebar left sticking up from the concrete. Because this concrete forms part of a hoistway, non-elevator related wiring is prohibited in the space. I'm thinking of having a piece of rebar bent downward (protruding below the pit floor slab) and welding to it before the slab is poured, then backfilling with sand/gravel or GEM to prevent concrete incursion. Any code issues with this? Is it better to bury an exothermic weld in the concrete? I'm not really comfortable with copper in direct contact with concrete as a general principle but this situation is a bit unusual.

--thanks

 

[W=EI]

I would prefer an exo Ufer to a made GEC anyday. I would imagine that Cadweld is listed for encasement in concrete but you should check on that. Hopefully the Ufer is tied into the electrode system for the bldg. service if not then do so...NEC 250-66.

 

[swei]

Erico confirms that CadWeld is perfectly OK buried - either in soil or in concrete. We will weld up a few bars and bond to those along with the rods.

thanks...