nolabama

Would drilling something like a concrete sleeve anchor in a pad and bolting a lug to it be legal for pad bonding?

sleeve anchor is pictured here http://www.confast.com/products/conc...ve-anchor.aspx

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RIVETER

Is this a serious question? I ask this because I sometimes get ripped for someone not understanding my humor, or my not understanding theirs. I mean no harm so I will answer...seriously. If I were to pour a concrete pad knowing that I may want to ground it, I would insert iron mesh and bond all sections and then drive a ground rod.I am not the authority but that would be the minimum that I would do.

BuzzKill

negative...you have to get to the rebar in the pad.

nolabama

Yes this is a serious question. No this is not for a new pour. If you need to bond something -like the hot tub in the other thread- to an existing concrete pad would this anchor be legal? Its just bonding the EGC not the GEC is it not?

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william1978

Just take a angle grinder and cut a grove with a diamond tip blade and then push the #8 down in the grove.

RIVETER

I am not the foremost guru, that may be PeterD, but I would want lightning protection as best as I could...that rings of grounding to earth. AS far as the hot tub electrical, it is a branch circuit, I believe, and the code spells it out.

BuzzKill

Gotta hit the steel in the pad in order to be sufficient, and then it needs to be bonded well.

RIVETER

Bonding and grounding are different even though they are at the same potential. Grounding has to do with EARTH grounding, via, an electrode, of some sort. Bonding has to do with whatever it takes to achieve THAT same potential.

BuzzKill

yeah whatever, you have to bond to the steel in order to have sufficient ground(ing).

RIVETER

You are correct...If you have building steel columns, they have to be considered as grounding electrodes.

leland

Then patch it in of course. Then seal it to match the existing. Done.

Thats a good answer William, and easy

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BuzzKill

Sounds hack-y.

RIVETER

It is. There is so much mis information or misunderstanding about grounding/bonding, it could be a subject unto itself.

BuzzKill

Sounds great! And then when there is a ground fault on the equipment, whoops! it won't clear and someone gets bit.

qckrun

Exactly why do you think there were so many changes to section 250 in the 08 code lol.

RIVETER

I've not seen the changes...I just kind of know.

nolabama

Bonding structural steel to the GEC for lighting protection is not what I am talking about. I can see, however, where you would want to bond to the steel in the concrete. I don't see how a wire put in a groove cut in the concrete is much better that what I have suggested, and might take longer too. So for an existing concrete pad that needs to be bonded the only correct way is to break concrete and bond to the rebar?

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waco

No. Obtaining an equipotential grid goes much farther than that and yes, inserting a wire into a cut in the slab looks as good as the real thing, but it doesn't get it done.

Portable pools/tubs don't require equipotential grids, but some sort of non-conductive surround wouldn't be a bad idea. I wouldn't get in a hot tub if I had to, but I'd sure rather step into one from an insulated rather than a non-insulated surface. I'm thinking about those weird effects of damaged underground service conductors and bare feet on a wet concrete floor and bare hands in the water.

nolabama

If they dont require equipotential grids then what is the point?

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william1978

I talking about 680.26. Just what kind of faults are you talking about?