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#93284 - 05/11/05 09:54 PM 680.26 Bonding Grid  
shortcircuit  Offline
Member
Joined: Jun 2004
Posts: 608
massachusetts
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?

shortcircuit


2017 / 2014 NEC & Related Books and Study Guides

#93285 - 05/11/05 11:24 PM Re: 680.26 Bonding Grid  
gfretwell  Offline


Member
Joined: Jul 2004
Posts: 9,057
Estero,Fl,usa
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.


Greg Fretwell

#93286 - 05/12/05 06:49 PM Re: 680.26 Bonding Grid  
Tom  Offline
Member
Joined: Jan 2001
Posts: 1,044
Shinnston, WV USA
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


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#93287 - 05/13/05 02:15 PM Re: 680.26 Bonding Grid  
shortcircuit  Offline
Member
Joined: Jun 2004
Posts: 608
massachusetts
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

shortcircuit


#93288 - 05/14/05 10:27 AM Re: 680.26 Bonding Grid  
harold endean  Offline
Member
Joined: Feb 2002
Posts: 2,233
Boonton, NJ
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.


#93289 - 05/14/05 01:39 PM Re: 680.26 Bonding Grid  
gfretwell  Offline


Member
Joined: Jul 2004
Posts: 9,057
Estero,Fl,usa
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) ;-(


Greg Fretwell

#93290 - 05/14/05 02:17 PM Re: 680.26 Bonding Grid  
George Little  Offline
Member
Joined: Jan 2004
Posts: 1,489
Michigan USA
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).


George Little

#93291 - 05/14/05 02:35 PM Re: 680.26 Bonding Grid  
shortcircuit  Offline
Member
Joined: Jun 2004
Posts: 608
massachusetts
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 [Linked Image]

shortcircuit


#93292 - 05/14/05 02:48 PM Re: 680.26 Bonding Grid  
gfretwell  Offline


Member
Joined: Jul 2004
Posts: 9,057
Estero,Fl,usa
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.


Greg Fretwell

#93293 - 05/14/05 03:09 PM Re: 680.26 Bonding Grid  
gfretwell  Offline


Member
Joined: Jul 2004
Posts: 9,057
Estero,Fl,usa
I have a question in to copper.org to see if they have heard of a product and manufacturer.


Greg Fretwell

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