Ufer in a Metal Building

[eaube1]

New addition to existing building. The addition is 40,000 feet. The fountation has the approiate rebar stub from the foundation footing. The question that has come up is now the 15 interior collums in the center of the building. They are individual 10'x10'x2' chunks of concrete with rebar in them. Do each of these need to be grounded too?

 

[jumper]

You only need one GEC to the foundation rebar. The rest of the steel columns should be bonded by the interlocking building steel, often the roof trusses and steel header beams between columns.

 

[infinity]

Even if the structure is built so that it has multiple CEE's you only need to use one.

 

[petersonra]

Even if the structure is built so that it has multiple CEE's you only need to use one.

and if there is one in the existing part of the structure you don't have to do anything as far as CEE goes.

 

[Smart $]

The structural metal needs bonded 250.104(C), but just going by what you describe, the columns are not grounding electrodes 250.52(A)(2).

 

[eaube1]

and if there is one in the existing part of the structure you don't have to do anything as far as CEE goes.

That's exactly what we have multiple CEE but where does it say I only need to use one. I am being told I have to use them all


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[infinity]

Not required by the NEC:

250.52(A)(3) Concrete-Encased Electrode. A concrete-encased elec-trode shall consist of at least 6.0 m (20 ft) of either (1) or (2):
(1) One or more bare or zinc galvanized or other electri-
cally conductive coated steel reinforcing bars or rods of
not less than 13 mm ( 1 ⁄ 2 in.) in diameter, installed in
one continuous 6.0 m (20 ft) length, or if in multiple
pieces connected together by the usual steel tie wires,
exothermic welding, welding, or other effective means
to create a 6.0 m (20 ft) or greater length; or
(2) Bare copper conductor not smaller than 4 AWG
Metallic components shall be encased by at least 50 mm
(2 in.) of concrete and shall be located horizontally within that
portion of a concrete foundation or footing that is in direct
contact with the earth or within vertical foundations or struc-
tural components or members that are in direct contact with
the earth. If multiple concrete-encased electrodes are present
at a building or structure, it shall be permissible to bond only
one into the grounding electrode system.