Our department has come up with three solutions for the new deck bonding requirements in the 2005 NEC.

1. The rebar used to form the pool shell can be extended 3' into the deck area. 2. The standard 6x6 welded wire mesh can be bonded to the pool rebar or other point on the equipotential grid. 3. The alternate means stated in (part 3) of the section can be constructed.

Now, a few of the other surrounding jurisdictions are objecting to us permitting the wire mesh to be used. They claim the bonding grid cannot be less than typical ½" rebar or #8 copper. They feel the wire mesh is not suitable.

I referenced the similar bonding requirements in Article 547 that clearly identify wire mesh, however they feel the section and allowance in this article cannot apply to pools or the deck.

What are thoughts on the issue? The wire mesh will certainly provide the equipotential gradients along the deck and satisfy what I believe is the intent of the section, though wire mesh is not specifically referenced in that section.

(On a side note, I have been hearing a rumor from a very good source that another TIA is soon being released removing this entire new wording all together - or at least the part about the paved decks)

The wire mesh is not one of the methods permitted in the 2005 code. However, the 2008 has been rewritten, and I just received word back from the code panel meeting in California that the panel will accept the wire mesh as a bonding grid. I don't know if that wording will be included in 2008 NEC, (it's not included in the 2008 draft), but they seem to say they will accept it.

I just don't know how we can accept something if it is not written in the code, or how we can accept something from the 2008 cycle when we are just adopting the 05?

I agree that is how it reads. (6x6 steel wire is not acceptible) but I am not sure why not.BTW pools are usually built with #3 rebar AKA 3/8" 12" O/C.

This is kind of strange because last week I had to instruct an entire jurisdiction on this and how to do this. The plans examiners wanted answers as they will get asked questions all day about this subject. I told them something very similar, if not exactly what Bryan has just said. Read the wording in the code again:

(C) Equipotential Bonding Grid. The parts specified in 680.26(B) shall be connected to an equipotential bonding grid with a solid copper conductor, insulated, covered, or bare, not smaller than 8 AWG or rigid metal conduit of brass or other identified corrosion-resistant metal conduit. Connection shall be made by exothermic welding or by listed pressure connectors or clamps that are labeled as being suitable for the purpose and are of stainless steel, brass, copper, or copper alloy. The equipotential common bonding grid shall extend under paved walking surfaces for 1 m (3 ft) horizontally beyond the inside walls of the pool and shall be permitted to be any of the following:

(1) Structural Reinforcing Steel. The structural reinforcing steel of a concrete pool
where the reinforcing rods are bonded together by the usual steel tie wires or the equivalent


The code is "admitting" that the grid is held together by the little steel twisty ties. THAT is what is making the contact between the structural bars and forming the grid.

I instructed the plans examiners to make sure that ALL of the STRUCTURAL REINFORCING STEEL needs to be left extended such that 3' of the STRUCTURAL REINFORCING STEEL can be bent outward into the deck. Then mesh would be added (EQUIVALENT to the steel twisty ties, in my opinion) to form a 3' grid around the pool.

The #8 would have to be clamped to the STRUCTURAL steel to ensure a good connection, in my opinion.


So there's the grid.


Comments please.

Again the code calls for structural bars forming the grid....same as the construction of the pool.

I'm not saying that the wire mesh won't work...I just don't see how we can permit something that the code doesn't.

If every #3 that comes up to the tie beam is bent and extended under the pool deck for 3 feet all they need to add is two #3s to ring the deck at 2' and 3' out. There is already one at the top of the tie beam. That will be a 12x12 matrix. They might have to put some short pieces in the corners to pick up the radius.
It would probably be cheaper and definately easier for pool "steelers" than using mesh.
I don't think you need any special bonding for the deck of this is simply extended pool steel, which is already bonded.

Personally I bonded my pool steel with a #8 cu ring tied to every 20' stick on the bond beam and brought out 6 #8s for my pool cage bonding but I am a fanatic about grounding/bonding. I think my pool cage is really a faraday cage that save us from a lightning strike if it is bonded well.

I believe the writers of 680.26 believe the Ufer concept that the concrete is actually what makes the electrical connection between tied rebars.

Article 680.26 (C) Equipotential Bonding Grid.
The equipotential common bonding grid shall extend under paved walking surfaces for 1 m (3 ft)horizontally beyond the inside walls of the pool and shall be permitted to be any of the following:
(1) Structural Reinforcing Steel. The structural reiforcing steel of a concrete pool where the reinforcing rods are bonded together by the usual steel tie wires or the equivalent.

This would be an extension of the pool forming steel out 3 feet from the inside wall of the pool in a grid formation just as exibit 680.14 of the handbook shows. Nothing less nothing more.

"a network of uniformly spaced horizontal and perpendicular lines" definition from websters of a grid.

If it was a metal liner pool we would go to (2).

We would also give them the option of the alternate means exactly as described.

I was notified by Koert Van Wormer (City of Melbourne) that they are accepting the 6X6X10 WWF. He also mentioned the rest of Brevard County is as well.

I think with all these ideas we are designing something that is not the intent of the code.

(1) Structural Reinforcing Steel. The structural reinforcing steel of a concrete pool where the reinforcing rods are bonded together by the usual steel tie wires or the equivalent.


Question: If the pool is engineered (which it is) and the engineer specifies the structural steel to stick past the pool into the deck (3'), and be connected by the mesh -- then doesn't that satisfy (1) above?


Why or why not.