concrete bonding

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krstuddard

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I am a custom home builder that just built an 8000 sf barn with a concrete aisle. As a bonified farm, no permits were required except electrical. We poured over 3000 sf concrete with fiber mesh, no rebar and now they say we have to tear it all up and put in bonding. Is there any way around this? Maybe a ring or rods or something like that. PLEASE help as my electrician has no idea what to do and the head electrical inspector only says to tear the concrete up and redo with bonding mesh or rebar...There has to be some other way. Thanks in advance for any advice.
 
iwire

iwire

Moderator
Staff member
Location
Massachusetts
Re: concrete bonding

I think your screwed.

547.10 requires an equipotential planes established in livestock areas.

2002 NEC, 2005 is much the same.

547.10 Equipotential Planes and Bonding of Equipotential Planes.

For the purposes of this section, the term livestock shall not include poultry.

(A) Areas Requiring Equipotential Planes. Equipotential planes shall be installed in all concrete floor confinement areas of livestock buildings that contain metallic equipment that is accessible to animals and likely to become energized. Outdoor confinement areas, such as feedlots, shall have equipotential planes installed around metallic equipment that is accessible to animals and likely to become energized. The equipotential plane shall encompass the area around the equipment where the animal stands while accessing the equipment.
Click to expand...
The only ways out that I see are the following.

1)Never bring livestock in this building.

2)Remove all metallic equipment that is accessible to animals and likely to become energized.

3)Rip up the slab and install the equipotential plane.

Good luck, concrete with fiber mesh is not easily removed.
 
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pierre

Senior Member
Location
Westchester County, New York
Re: concrete bonding

I have not seen the ASAE EP473-2001 standard for equipontial planes in animal containment areas, but Bob's suggestion sounds like something I would present to the inspector.

"maybe you could lay some wire mesh or re-bar on top of the slab and pour another 1" slab on top of the existing slab."
 
George Stolz

George Stolz

Moderator
Staff member
Location
Windsor, CO NEC: 2017
Occupation
Service Manager
Re: concrete bonding

I'm no concrete guy, but I don't believe that would work.

Heavy cows, 1" of concrete on top of another slab that's weeks old, sounds like a tectonic plate scenario. :eek:
 
catchtwentytwo

catchtwentytwo

Senior Member
Re: concrete bonding

You probably have to use a minimum of 2 inches (with proper prep of the existing slab)for a concrete cap. Maybe more because of the mesh. A concrete supplier or masonry supply firm could help with determining what product(s) or methods might work.

It'll come down to the cost for a 3000 square foot "fix" versus the Pneumatic Eraser Solution.

[ August 30, 2005, 07:48 AM: Message edited by: catchtwentytwo ]
 
K

krstuddard

Member
Re: concrete bonding

Hello all,

Thanks for all your help. I am working on a 3 inch slab overpour solution with 4000 psi concrete. I think this will work. Just hoping for other options. I really do appreciate the prompt replies. Especially the Pneumatic eraser!!.

Ken
 
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hardworkingstiff

Senior Member
Location
Wilmington, NC
Re: concrete bonding

I wonder if you were to cut 1" to 2" deep saw cuts in the concrete on 12" centers and install your #8 ground wire in it then grout over top of it? The joints would have to be soldered I guess since you could not get a split bold in the saw cut. Just a thought.
 
K

krstuddard

Member
Re: concrete bonding

I thought of the cutting concrete idea, but cannot find the requirement about the 12" OC spacing as as been said before. I looked everywhere on the internet for the definitive answer and could not find it at all.

Thanks for the contimued input.

Ken
 
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petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
Re: concrete bonding

the code does not seen to specify just what type of a grid is required. only the size of the bonding wire connected to the mesh or other conductive elements used inside the concrete.

I don't see anything that would require you to use #8 copper as the conductive elements inside the concrete pad. I don't see any reason to use expensive large copper wire. If mesh is adequate (which is a small gauge steel wire), why couldn't you use some kind of steel wire in the slots you cut. maybe like the steel wire you see run along the bottom of chain link fences. It certainly meets the "other conductive element" requirement.

I also don't see any requirements for how the conductive elements are spaced in the concrete pad. Maybe an X shape from corner to corner and a ring around the outside perimeter would be adequate.

I guess in the end, the reason for the grounding would need to be considered. You don't want your critters to be negatively affected, so you need to make the grounding grid adequate to prevent problems with the critters.

[ August 31, 2005, 09:58 AM: Message edited by: petersonra ]
 
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