ECN Forum Forums Code Related Discussion NEC & other Code issues 680.26 Bonding Grid

680.26(C) 2005 NEC requires the equipotential bonding grid to extend under "PAVED" walking surfaces for 3 feet beyond the inside walls of the pool...

Would precast brick pavers laid in stone dust used around pools also require the bonding grid?

Or was the CMP intending the grid to be established under poured concrete pool decks only?

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The Fl IAEI had a long conversation about this and the short answer is "yes" you need the grid. I expect there will be a welded wire product soon if it is not here now. Otherwise you better get a good crimper and a buttload of "listed pressure connectors".
I have heard a rumor that they might take a "square wave" pattern using one conductor.
They also say this grid must be UNDER a fiberglass spa or pool. That one I do not understand.
ROPs close this fall.

I've been involved indirectly with he question of the grid going beneath a fiberglass pool. There will be a TIA coming out later this year that makes it clear that the grid only needs to be under the walking surface within 3 feet of the pool and does not have to extend under the fiberglass pool.

Tom

Thanx for the replies...

So, I have to rewire an exsisting concrete inground pool that will have fiberglass applied to the surface of the pool shell.

This is what I am planning to do...

1) Break into the concrete wall to expose the rebar within and attach a new bond. Break into the concrete to get to the ladder cups to attach a new bond.

2) Install a #8 solid copper equipotential bonding grid around the perimiter of the pool under the new brick pavers set in stone dust that will be installed.

3) Install a new feeder to the pool pump location with a sub-panel to provide power for all pool area equipment, etc.

Questions...

1) Has anyone built a bonding grid on site yet?

2) Has anyone busted into a concrete wall of a pool and successfully rebonded a pool shell?

So far I couldn't find any exsisting bonding wires in the 30+ year old pool to use, so the proposed invasive procedure is my only alternative.

Any tips would be helpful...

thanx

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I don't know if this helps but I just saw an old pool where the decking was removed and they want to install a new liner. The supports all around the pool are ( I believe) aluminum and they are directly buried in the soil. The EC is going to use UL approved diect burial lugs that are rated for AL and bond each upright post ( about 40 of them), then connected it back to the filter and the pool ladder and cups will attach to this pool bonding grid.

Does it have a light? You might try top megger the ladder cups to each other and the light niche to see it it is all bonded. Igf you can determine that there is already some good bonding within the pool structure you might get away with simply finding the most easily acceptible point of the steel to go on to the pump.
Is it possible to research the original permit to see if it was inspected? Pool bonding is an old rule. Busting into a pool shell is a pretty risky adventure and if they later have a problem you know they will blame you. (or at least try) ;-(

Harold- I didn't know that UL "Approved" anything nor have I ever see Al lugs suitable for Direct burial Plus the code is pretty specific about material for lugs. See 680.26(C).

gfretwell...There is no light, as it was removed and sealed over years ago. I talked with the pool guy who is retrofitting the concrete shell with new plumbing...3 jets and a surface skimmer/intake circulating system. He said the pool pre-dates gunite, maybe 40 years old. They would set up forms and pour walls like a foundation in a house.

Well, when they cut in the skimmer they found rebar. I will not do cutting myself...they will. He also said it may be easier to just replace the ladder for bonding purposes.

1)How would megger test be done?
2)Would a simple continuity test work?

The only visible bonding is a stranded #8 from the pump to the grounding bar of the old rusted sub-panel inside the pump shed.

I told the homeowner and the pool guy that all wiring must be brought up to 2005 code and that I would not be involved unless it was done so.

I look forward to the challenge of fabricating one of the first equipotential bonding grids out of #8 solid under the pavers around the pool...jus hope the customer can swallow the cost of the installation

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If you have exposed rebar and a listed connector that should work for the inspector for the basic bonding. I would really want to see <1 ohm with a simple continuity test (rebar to ladder cups) but it would be better if you loaded it a bit. I would trust my Ecos tester. Maybe with the right adapter a Suretest would work too, never tried it.
I am curious, what are you using to splice the #8 at the intersections? Bugs will work but that will be pricy. I think I would beat up the internet and suppliers to be sure someone has't come up with #8, 12x12 welded copper mesh. It is the logical product for this application.

I have a question in to copper.org to see if they have heard of a product and manufacturer.

gfretwell...

For the perpendicular intersecting #8 bonding wires of the equipotential grid pattern, I will use split bolt connectors...unless someone knows of a new product for this application?

I'm still in the design stage of rewiring this exsisting inground poured concrete swimming pool.

The deck surrounding the pool will be precast brick pavers set in stone dust... so the bonding grid under the deck would have to be placed under the layer of stone dust...

As for a grid under a fiberglass pool structure, here is the latest from the NFPA...

Go to: www.nfpa.org/itemDetail.asp?categoryID=136&itemID=19181 and click on "May 2005" from the list...

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George,

The Bonding Lugs I saw that looked AL, I believe were a type of metal that was "Tinned" to be UL acceptable for attaching to AL and they were suitable for direct burial. I will try to get more info on these lugs for you if interested. They are something brand new I guess, cause I never seen them before. I believe they were from Greeves.

Copper.org gave me 2 links to copper grid systems.
Erico (the Caddy Clip guys) makes a copper clad steel grid http://www.erico.com/products/GroundGrids.asp

Harger Lightning Protection makes a U/L listed #6cu grid http://www.harger.com/catalog2004/1_4_8.pdf

I don't know if either either of these is cheaper than a field built #8.
If the demand is there these would be the logical folks to cobble up #8 grids tho.

I don't think that is a listed use of split bolts.
Don

Split bolt is a regular way to join 680.26 conductors. As long as it is listed for direct burial and copper I don't see an issue. It would be pretty expensive to do one on every corner of a 12" grid tho.
The Erico folks say they make it prewelded and ready to go. I looked at the catalog and didn't see a 3' wide mat. They seem to be 4'
If you are really buying some I imagine the salesman would be happy to talk to you.

gfretwell...thanks so much for the supplier leads!

I put a call into HARGER and they gave me a part# for a mesh with #8 solid with welded joints 100ft long by 3ft wide...GM3100812

Coarse they won't sell directly, so I'll check with my supplier tomorrow for pricing.

I told him there is a demand for a suitable product in the pool industry.

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Actually I got those tips from copper.org but I was glad to help find an answer to this problem.

resqcapt19.."Burndy Servit" split-bolt type KS-DB is UL approved for direct bury in earth or concrete...

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I ordered pre-fabricated grounding mesh from HARGER today. It is going to be 2 feet wide and 160 feet long, #8 solid copper welded at intersecting points with 12inch cells.

This will cost $620 for the mesh and $120 shipping and will take 7 to 10 days to get to me.

I was also successful busting into the concrete from the backside of the wall and exposed 1" rebar at two points for bonding the pool shell.

So, the 2005 code has added a couple grand to the electrical bonding for this pool

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It looks great. This is the prefab mesh?


[This message has been edited by gfretwell (edited 06-29-2005).]

gfretwell...yes,this is the mesh from Harger that you helped me find...thanx again.

The installation was very fast with the prefab mesh that was 160 feet long. The mesh came all rolled up. Just roll it out down a side of the pool and cut.Then roll it out down another side and cut. Join the runs at the corners with split bolts. Then connect the mesh to a bond wire that runs between the pumps and pool rebar.

As you can see, the pool was basicly square. This was easy to install the mesh.If the pool had a rounded shape to the outer walls, it would be difficult to follow the wall with this prefab mesh.

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bump

Great replies guys.
But doesn't Article 680.26C come under permanently installed pools. And isn't an above ground pool an considere permanently installed pool and you have to bond that pool.
So does thes grid have to be around an above ground pool? If not, where do we get only inground pools need this grid?
Thanks

The key word here is "paved". If there is a paved surface around the above ground pool it needs to be bonded. Nothing says what elevation this paved surface has to be. It is just horizontally 3 feet. That would usually bite the guy who decided paving bricks would be a good solution to the mud next to the pool and were easier than concrete although concrete would still need wire in it, bonded to the grid.
In real life, if it was done after the pool was OKed I am not sure how this would be enforced.
A wood/Trex etc deck around the pool would not need the bonding grid.
The only pools that are exempt are "storables". I think you would be looking at the equipment installed when you made that decision. "Storable" pumps and lights are different than "permanent" ones and they are mutually exclusive. You would be looking at that at the 680.22 and 23 stage of your plan review.

Gfretwell:

Thanks for the "BUMP", I never saw this thread!

Joe Rossi:

Susan Borek (DCA)said "....above grd pools with decking 12" or larger REQUIRE this, same as IG

Got all the info I need

Thanks Guys

John

How do you bond a Trex deck? Weed Eater string and Tywraps?

;-) sorry

OK, I have a question.....
Regarding the pics of the install above, does not the Article require 3' of grid??

As I see the pics, and IF the material is 12" squares, I only "see" 2' (24")

John

edit:
Went back for a second look, & text read, still have question.

[This message has been edited by HotLine1 (edited 07-27-2006).]

The tie beam of the pool is the first foot

Gfretwell:
Thank you.

John

The code also requires a Equipotential Bonding Grid to be installed beneath paved surfaces surrounding Spas & Hot Tubs installed outdoors...680.42

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