New Industrial Building Grounding

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McCES

McCES

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I am designing the grounding system for a new industrial steel-framed building. The building is 100' x 25' with steel columns spaced 25' apart. Each column footing includes a rebar cage. There are also formed and poured walls between each column along the long walls.
Because the rebar is present in the footings I am planning to use it as my grounding electrode. My question is do I need to bond the rebar in the footing from each column? Can this bonding be accomplished by tieing together the footing rebar with the rebar in the walls?
I would typically design a ground ring around the perimeter of the building with pigtails to the rebar in the footings.
I need to run pigtails from the grounding system into 2 separate electrical equipment rooms as well.

Sorry for the lengthy explanation. Trying to satisfy a client who doesn't want a ground ring installed.
 
2008 NEC added a sentence in 250.52(3) which states that if you have multiple concrete encased electrodes that would serve as a grounding electrode, only one needs to be used. I suspect that they will all be tied together via building steel, but either way, as long as you use one, you are OK.
 
McCES said:
My question is do I need to bond the rebar in the footing from each column? Can this bonding be accomplished by tieing together the footing rebar with the rebar in the walls?
I would typically design a ground ring around the perimeter of the building with pigtails to the rebar in the footings.
I need to run pigtails from the grounding system into 2 separate electrical equipment rooms as well.
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No, yes, not required, and each can be bonded to nearest accessible part of electrode.
 
Thanks for the insight guys. It just doesn't seem right that the tie-wired rebar woiuld be as effective as copper and cadwelds to bond everything together.
 
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