Ground rod question

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RESI

Member
Location
Virginia
In a residential situation, can rebar in the garage concrete floor serve as the ground rod or do I still have to install 2 ground rods also? Thanks to all who reply!

May God bless you all.
 

A/A Fuel GTX

Senior Member
Location
WI & AZ
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Electrician
The rebar in the floor is not considered to be an electrode. The CEE must be in the footing. You must use all available electrodes and in your case, it sounds like ground rods are your only option.
 

infinity

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Staff member
Location
New Jersey
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Journeyman Electrician
If the rebar qualifies as an electrode then the ground rods are not required. Here's the requirement for a CEE:


250.52(A)(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 (? in.) in diameter, or consisting of at least 6.0 m (20 ft) of bare copper conductor not smaller than 4 AWG. Reinforcing bars shall be permitted to be bonded together by the usual steel tie wires or other effective means. Where multiple concrete-encased electrodes are present at a building or structure, it shall be permissible to bond only one into the grounding electrode system.
 

nosparks1

Member
As stated by others the straight answer is no. Most concrete floors I have seen are poured over stone or a vapor barrier which does not put the concrete in direct contact with the earth and is not at the same depth as a footer or foundation thus the requirement of having the rebar type electrode in the footer or foundation.
 

infinity

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Staff member
Location
New Jersey
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Where does that say that gnd rods are not required?

If you have a CEE (concrete encased electrode) then you do not need any other made electrodes. If there happens to be a water pipe electrode present then it must be used too.
 

A/A Fuel GTX

Senior Member
Location
WI & AZ
Occupation
Electrician
Where does that say that gnd rods are not required?

You must use all available electrodes. If you only have a CEE, that is all that's required. If you have no electrodes, you create one by adding the ground rods. If you have a water pipe electrode, you must supplement it with ground rods or other methods. Read 250.52 and 250.53 for more specifics.
 
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