I have a 4" metal sprinkler main entering a building under construction. It needs to be connected to the grounding electrode system with a 2/0 conductor. None of the catalogs I have show a grounding clamp of that size. The flange bolts on the sprinkler main are a much larger diameter than the mounting hole on a 2/0 lug. Any suggestions as to other methods of attaching the 2/0 conductor?

There must be some test ports, gauge ports, and other smaller pipes branching off of the main, no?

Just attach to one of these with an appropriate clamp, making sure that there is a solid metallic path back to the main pipe.

There are several manufacturers of pipe clamps for larger sizes. Try the Greaves G1 Series (800-243-1130, sorry, I don't have a web address for them).

I have used ILSCO in the past, prices were very reasonable. http://ebusiness.ilsco.com/webapp/w...gId=-1&catalogId=1&categoryId=77

Tom

Jsherrard,
I'd ask the guys that installed the pipework.
We use the same sized pipes here and we use the same sized clamps as the installers to bond our pipes.
Just make sure that there is good metallic contact ie: Low Resistance.