An inspector here in my county in VA is requiring me to ground the rebar & mesh in the concrete slab of a residential garage instead of using the suplemental ground rod(s) I know that I would have to use the ground rods normally in an existing bldg but he is telling me that code requires that the concrete encased steel is to be used in new building foundations. The garage will have its own meter (seperate service) Any answers for this?
Exterior bldg's
- Thread starter bigfoot
- Start date
- Status
- Location
- Simi Valley, CA
We have an ordinace that says a concrete incased electrode shall be installed where footings are availible. We require a #4 bare copper conductor.
Seperate structures require a grounding electrode.
Could be your answer.
Seperate structures require a grounding electrode.
Could be your answer.
Let me make sure I understand your question. I don't think you are asking whether or not the rebar needs to be there. I think you are saying that it is there, but you are asking if the code requires you to use it as a grounding electrode rather than using ground rods.
If I understand your question correctly, then my answer is yes, you are required to use the rebar as a grounding electrode. NEC 250.50 requires you to use all grounding electrodes that are present. Since the rebar is present, you must use it. You are not required to install any ground rods in this case, but if you do install them, then you must use them.
I agree with the others, but am a little concerned with the term "slab".
Per 250.52(A)(3) an electrode "within the concrete foundation or footer"
must be utilizied. If the rebar is only in the slab, I see no requirement to bond. In construction here, the rebar would be in the foundation.
Per 250.52(A)(3) an electrode "within the concrete foundation or footer"
must be utilizied. If the rebar is only in the slab, I see no requirement to bond. In construction here, the rebar would be in the foundation.
billsnuff
Senior Member
- Location
- East of 480sparky
An electrode encased by at least 2" of concrete and 20' of steel reinforcing bars or rod of not less than 1/2" in diameter......250.52A3 2008NEC
more exactly:
(3) Concrete-Encased Electrode. An electrode encased by at least 50 mm (2 in.) of concrete, located horizontally near the bottom or vertically, and within that portion of a concrete foundation or footing that is in direct contact with the earth, consisting of at least 6.0 m (20 ft) of one or more bare or zinc galvanized or other electrically conductive coated steel reinforcing bars or rods of not less than 13 mm (1/2 in.) in diameter, or consisting of at least 6.0 m (20 ft) of bare copper conductor not smaller than 4 AWG.
my contention being, that if, for some reason, the rebar was only in the slab, which was the wording in the OP, there is no Code requirement to use it as an electrode.
billsnuff
Senior Member
- Location
- East of 480sparky
mesh used in a slab on grade doesn't qualify, also, will there be visquine
under the concrete to eliminate moisture?
not enough info from the OP
and I agree with Augie
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