inground pool bonding

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  #1  
Old 09-08-06, 10:17 AM
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Question inground pool bonding

I am building a concrete block and rebar inground pool. All is done except the bonding. The #8 bonding grid wire from the footing rebar will be connected to the pump outside lug. I have a hayward 12 volt 300watt light niche with internal #8 bond wire back to hayward pool junction box and then 12 volt transformer. The outside grid lug on the outside of the light niche shell is attatched to #8 bonding wire, but---not to the grid ---I have a grid wire but it is too short to reach the lug. Can I bring both #8 wires up into a separted pool junction box just to connect them ? Electrical inspector said I can't splice any grid bonding wires. Seems like it would be fine if brought back up into an approved junction box though. Also, is it possible to bring the wire back to the pump lug instead since it already will be connected to the grid? Can more than one #8 bond wire be connected to the pump lug?---because next year I plan on putting in a diving board, but presently have no access to bond back to the grid itself (all covered--except small piece of durawall reinforcement wire), so can't I connect to the pump lug along with the #8 bond going back to grid? Any suggestions welcome. thanks
 
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Old 09-08-06, 10:22 AM
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[post removed.]
 

Last edited by racraft; 09-08-06 at 05:19 PM.
  #3  
Old 09-08-06, 11:49 AM
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Wink

?---because next year I plan on putting in a diving board,
Better check with your insurance company that and a slide is a sure no no. with them . Had to take nine out cost to much.

ED
 
  #4  
Old 09-08-06, 01:06 PM
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The bonding grid expalined in 680.26(C) may be spliced. There is NO requirement for it to be continuous and without splice...as long as listed connectors/splices are used. And exothermic welds are NOT the only listed splice.

If I am wrong show me the code section stating this is so.

See this page and graphic from a leading code expert's site:
http://www.mikeholt.com/mojonewsarchive/NEC-HTML/HTML/Article-680-Swimming-Pools-Fountains-and-Similar-Installations-V~20050206.php
http://www.mikeholt.com/onlinetraining/page_images/1014160805_2.gif
 
  #5  
Old 09-08-06, 02:13 PM
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"The outside grid lug on the outside of the light niche shell is attached to #8 bonding wire, but---not to the grid ---I have a grid wire but it is too short to reach the lug. Can I bring both #8 wires up into a separted pool junction box just to connect them ? Electrical inspector said I can't splice any grid bonding wires. Seems like it would be fine if brought back up into an approved junction box though."

So if I'm understanding you have back filled the pool and can no longer make connections to the rebar. If your putting a concrete walkway around the pool there should be a grid under it and it should be connected to the rebar. All of this would be your equipotetial grid. If so this grid under the walkway is a connection point.
The bonding wire that is too short to reach the niche lug must mean you cant get to to where it attaches to the rebar. I believe the inspector will allow you to join it in an approved swimming pool JB. They also may allow you to drive a 5/8 ground rod... attach the short wire to it with approved clamp and then run a # 8 from the niche lug to the ground rod. You have sorta caused yourself some grief by not giving yourself the ability to connect to the equipotential grid with your bonding wires. As for the diving board you have the same problem. You will need to run a #8 to the area of the diving board for future connection.
The inspector may allow you to do any of these. He may say no to all. But no inspector will let you spice the actual bonding wire and I havent met one that will let you use the bonding wire from another piece of metal or equipment to join to.

"Also, is it possible to bring the wire back to the pump lug instead since it already will be connected to the grid?"

Are you talking about the wire that is to short to reach the wet niche?

Can more than one #8 bond wire be connected to the pump lug?

No, but ask the inspector. He may allow you to add a lug. Thing is you dont bond to the pump... then use its bonding wire to join other metal parts with the equipotential grid. If this were allowed and you had several metallic pieces bonded to one point and those pieces using one common bonding wire to the grid, if that wire fails or breaks you lose your bonding to the grid for all the other metal parts. I think this is where you got into trouble by thinking you could connect to the short (bonding) wire coming off the rebar. This would not be the grid per se but just a bonding wire that should be connected to a piece of metal or equipment.

Roger
 
  #6  
Old 09-08-06, 03:55 PM
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pool bonding

thanks again for the info--sent private message--not sure if you got it. Does the equipotential grid under the brick path I plan on doing have to be connected to the pool grid rebar? They sell grid rolls 2ft wide I hear for this purpose. Again, maybe I'm just better busting hole in pool wall from outside and exposing some rebar--then I assume I'll just connect a whole bunch of grid boning wires all long length to reach anything in future I might possible add! What happens normally if somebody adds something metal close to pool --how do they get to the grid if all is closed up?
 
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Old 09-08-06, 04:58 PM
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Just as you have planned on adding yours.

Is it correct? with the propper connectors, as Speedy eluded to yes.

Again, The FIRST and formost consideration should be to the safety and integrity of the instalation.
The code directs you. YOU LIVE with it!
 
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Old 09-08-06, 05:18 PM
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Speedy,

I sit corrected. I was told incorrectly for my own pool that the bond wire needed to be continuous. Perhaps that used to be the case, or perhaps the information I was given was incorrect.

I have examined the current 2005 code, and you are correct, there is no requirement for the wire to be continuous.
 
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Old 09-08-06, 05:39 PM
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POOL,

The "equipotential grid" is a theoretical thing that you create. They are not referring to any specific rebar or steel prefab grid.
All the items bonded together form the equipotential bonding grid.

Depending on the code cycle you are folloing in your area things can be different. In 2005 they re-wrote a good bit of the important parts of this requirement.

Basically EVERYTHING within 5' of the pool must be hit. If there is rebar under the walk, yes, it should have been bonded. Now, rebar can be easy since if it is tie wrapped as it typically is you only need to hit one spot. If there are isolated sections of rebar each section must be hit.
If you are under 2005 you MUST have the grid extend out from the pool wall if it does not already.

Here is the handbook commentary on this if it helps:

The requirements for creating the equipotential bonding grid are substantially revised in the 2005 Code. First, the use of an 8 AWG, solid copper conductor or brass rigid metal conduit as the equipotential bonding grid is no longer recognized. This change precludes, for example, the use of an 8 AWG solid copper conductor encircling the pool perimeter as an equipotential bonding grid. The 8 AWG conductor and/or the metal conduit can be used as the method for connecting electrical and nonelectrical equipment to the bonding grid. Exhibit 680.14 illustrates the use of brass rigid metal conduit or other corrosion-resistant metal conduit as a means to connect electrical equipment, such as the forming shell of a wet niche luminaire, to a common bonding grid comprised of the pool reinforcing steel.
The second change regarding the types of permitted equipotential bonding grids is the recognition of a field-fabricated bonding structure that can be employed in the absence of structural reinforcing steel (which could be a result of nonconductive encapsulation) or bolted or welded metal pool walls. This ``alternate means'' as described in 680.26(C)(3) is required to ``cover the contour'' of the pool. What that means is that the field-fabricated bonding grid has to cover the entire outside outline of the pool structure, as would be the case with reinforcing steel or with bolted or welded metal walls. In addition to covering the pool contour, the bonding grid is required to extend horizontally into the deck area for not less than 3 ft. This 3-ft horizontal extension for the pool deck is required for all pool installations, including those with exposed reinforcing steel and those with bolted or metal walls.
 
  #10  
Old 09-08-06, 10:40 PM
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For sake of clarification and not agrument there is a grid. "The equipotential bonding grid. All metal parts specified in 680.26(B) must be bonded to an equipotential bonding grid 680.26(C) with a solid copper conductor not smaller than 8 AWG. The termination of the bonding conductors must be made by exothermic welding, listed pressure connectors, or listed clamps that are labeled as suitable for the purpose. An equipotential bonding grid must extend under paved walking surfaces for 3 feet horizontally from the water [680.26(C)]."
so the "grid" is a structure ...680.26(C)(1)..(2)..(3)a,b & c tell you what it can be. The metal parts and equipment that require connection (bonding) to the "grid" are done so with equipotential bonding conductors (8 awg bare/insulated copper wire). Those connections are made to the "grid" and metal parts in accordance with art. 250.8
The "grid" must be constructed correctly whether it is structural rebar, metal walls of a pool, or a man made 12" x12" 8 awg solid copper grid that conforms to the contour of the pool itself. The components of the grid are bonded to each other...ie...the rebar is wire tied (bonded) where it crosses or intersects. It should be, in the case of a pool, constructed in a crossing pattern or grid. You then run 8 awg bonding conductors from it out to your circulating equipment and metal parts such as ladders and fences...etc.

Though I think we are splitting hairs I do believe the intent of the code is to seperate the equipotential grid as its own entity. To which the metal parts within 5 feet of the pool walls and circulating pumps are bonded via the 8 awg copper conductors.

Roger
 
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Old 09-08-06, 11:01 PM
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I have often wonderd.......... How does that #16 steel tie wire totaly bond the re-bar? It's not even twisted tight. The sole purpose of it is so it won't move on the pour. Won't that break down first?
 
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