Grounding rebar

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Welcome to the forum.:)

There is no requirement that rebar installed in a concrete slab be bonded.

Rebar that meets the requirements of 250.52(A)(3) must be used as a gounding electrode. But rebar in a slab does not meet the requirements.

Chris
 
ade_tracy,

Just so you know, your not grounding the re-bar, A 'concrete encased electrode' is used

to ground the electrical system, not the other way around.
 
ade_tracy said:
Some individuals say all rebar, inside a slab in a process area, shall be grounded. I cannot find this in the code book.
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I have a question about your post. What are you defining as a process area? Is this in a meat packing plant? If it is, then it would truly seem odd to me that there would be such high regard for the comfort of the beast about to get herself slaughtered in short order...... Equapotential bonding grid????
 
macmikeman said:
I have a question about your post. What are you defining as a process area? Is this in a meat packing plant? If it is, then it would truly seem odd to me that there would be such high regard for the comfort of the beast about to get herself slaughtered in short order...... Equapotential bonding grid????
Click to expand...

Lake Jackson, TX is near Houston - I'm assuming process area means refinery or chemical plant.

Grounding and bonding requirements for petrochemical plants go way beyond NEC requirements, and are outlined in API 540 and each company's set of installation and design standards.

I work in a refinery and we are not in the habit of bonding rebar in slabs. We install a ground ring to typical NEC standards (but much larger wire) around each major foundation and we bond all of these seperate ground rings together. At least one bonding wire is connecting from the ground ring to the frame of the piece of equipment on the foundation - exchanger, drum, pump, motor, compressor, etc. This forms a ground grid throughout the process unit. Substations are grounded in accordance with IEEE 80 and the substation ground grid is tied to the process unit ground grid. All of our cable trays are listed for grounding and are bonded to the ground grid every 100 ft to minimize touch potentials. A bare copper ground wire is run on top of all duct banks and bonded to the ground grid at both ends.

All of this is in addition to running an EGC with each circuit, including circuits inside of conduit. We end up with a grounding system with many redundant parts to ensure an adequate fault current return path even if multiple bonds fail.
 
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