pool bonding without rebar in concrete

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  #1  
Old 03-28-06, 08:50 AM
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pool bonding without rebar in concrete

I'm getting new stamped concrete poured around my 20 plus year old gunnite pool. I was told that since there won't be any rebar in the concrete there's no need to bond the ladder, handles and diving board base. Is this correct? Should I tie all the above together with awg8 ground wire?

Thanks,

Larry
 
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  #2  
Old 03-28-06, 09:33 AM
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Larry:

Nec 680.26(B)(5)2....requires all metal withing 5 feet of the inside walls of the pool to be bonded with #8 copper to the bonding grid, this includes ladders and diving platforms. the fact that you have no rebar in the concrete has no bearing on whether you bond the diving board structure.
 
  #3  
Old 03-28-06, 09:56 AM
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If there's no rebar what qualifies as a bonding grid?

Thanks
 
  #4  
Old 03-28-06, 10:09 AM
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Copied section..... author Wgoodrich.... Installation above and inground pools....bonding grid description

http://www.selfhelpandmore.com/homew...bove/index.htm

http://www.selfhelpandmore.com/homew...perm/index.htm





BONDED PARTS.

THE FOLLOWING PARTS SHALL BE BONDED TOGETHER. IT IS THE INTENTION, THAT THESE PARTS BECOME ONE, AND THIS BONDING GRID DOES NOT USE AN ELECTRICAL GROUNDING SOURCE. THE BONDING GRID IS INTENDED TO MAKE ALL METAL PARTS “AS ONE ENTITY”, TO AVOID A DIFFERENCE OF POTENTIALITY BETWEEN THE WATER, AND OTHER PARTS OF THE POOL. A BONDING GRID CONSISTS OF A # 8 BARE COPPER, OR LARGER. ANY METAL PART SHALL BE A PART OF THIS BONDING RING. SUCH AS: METAL OF DIVING BOARDS - METAL OF STEP SYSTEM’S - METAL OF LIGHT FIXTURE ENCLOSURES - POOL SHELL - ALL METAL PARTS THAT ARE 4” SQUARE OR LARGER, METAL COPING STONES, IF METAL - ANY DECKING, IF METAL - ANY OBSERVATION STANDS, IF METAL, - ANY FENCING, IF METAL - METAL PARTS OF SLIDES - POOL DRAINS, IF METAL - ALL METAL FITTINGS {4” SQUARE OR LARGER} WITHIN, OR ATTACHED TO, THE POOL STRUCTURE - ELECTRICAL EQUIPMENT THAT ARE ASSOCIATED WITH THE POOL WATER CIRCULATING SYSTEM, INCLUDING THE PUMP, IF METAL - METAL PARTS OF THE POOL COVER, IF USED - ALL MOTORS ATTACHED, OR OPERATING THE POOL, IF METAL - ALL FIXED PARTS WITHIN 5' OF THE INSIDE WALL OF THE POOL, AND WI THIN 12' ABOVE THE POOL WATER LEVEL.

EXCEPTION:

ANY METAL PART IS NOT REQUIRED TO BE A PART OF THE BONDING GRID, IF THE DIMENSION OF THAT METAL IS LESS THAN 4", AND IF THAT 4” SQUARE METAL PART DOES NOT ENTER INTO THE POOL, AT LEAST 1".

680/22/B

STRUCTURAL RE-ENFORCING STEEL, OR THE WALLS OF BOLTED, OR WELDED METAL POOL STRUCTURES SHALL BE PERMITTED, AS A COMMON BONDING GRID, WHERE CONNECTIONS CAN BE MADE WITH A CADWELD, APPROVED LUG, OR OTHER {UL} APPROVED CONNECTOR.
 
  #5  
Old 03-28-06, 10:43 AM
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Larry, before I begin, I need to caution you that pool areas are one of the more difficult aspects of the NEC to comply with. Article 680 (which governs these installations) is chock full of very important and tricky requirements. I'd strongly recommend you seek out a professional for this project. That said...

Originally Posted by lumpy1
I'm getting new stamped concrete poured around my 20 plus year old gunnite pool. I was told that since there won't be any rebar in the concrete there's no need to bond the ladder, handles and diving board base. Is this correct? Should I tie all the above together with awg8 ground wire?
This is more involved than you may realize. Without rebar in the new concrete, then you need to create your own equipotential bonding grid around the pool. This is copied directly from the relevant section in the NEC:

NEC 2005, 680.26(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 (This is what you don't have.)
(2) Bolted or Welded Metal Pools. The wall of a bolted or welded metal pool
(3) Alternate Means. This system shall be permitted to be constructed as specified in (a) through (c):
a. Materials and Connections. The grid shall be constructed of minimum 8 AWG bare solid copper conductors. Conductors shall be bonded to each other at all points of crossing. Connections shall be made as required by 680.26(D).
b. Grid Structure. The equipotential bonding grid shall cover the contour of the pool and the pool deck ex-tending 1 m (3 ft)horizontally from the inside walls of the pool. The equipotential bonding grid shall be arranged in a 300 mm (12 in.) by 300 mm (12 in.) network of conductors in a uniformly spaced perpendicular grid pattern with tolerance of 100 mm (4 in.).
c. Securing. The below-grade grid shall be secured within or under the pool and deck media.
You need to know, that this bonding is very important because unless the entire area is brought to the same potential by bonding (hence the name, "equipotential bonding"), then users of the pool are at risk of shock whenever they touch unbonded metallic components of the pool. In addition, the grid is to minimize "step potential" which, as it sounds, is to eliminate the chance that dangerous voltage can travel from one bare foot, through the user's body, out the other foot, due to a difference in potential over a few feet. This is why the grid is required for three feet around the pool.

You might be thinking, 'No big deal, there's no lights or electrical equipment in my pool anyway. I can skip this.' If there is no electrical equipment in the pool itself, you're still not out of the woods, believe it or not. A problem with a local utility company can generate "transient voltages", because the utility uses the earth in their systems too. So a failure of some kind in your service, or your neighbor's service, can result in current passing through the soil in your backyard seeking it's source at the local transformer, or a remote substation, depending on the problem.

People immersed in water are very vulnerable to current, as saturated skin is an excellent conductor.

I'm not blowing smoke, not trying to frighten you, not trying to score a sale. You should find a qualified electrician to help you. A pool is just no small matter.

I hope this helps, and good luck.

-Rocky

P.S. A question I have is, how are they keeping your concrete intact with no rebar reinforcement?
 
  #6  
Old 03-28-06, 10:48 AM
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Check with your building inspector to find out what version of code is followed in your area.

The 2005 code actually requires you to create an 'equipotential bond' that includes the paved area around the pool.

See, for example http://electrical-contractor.net/ubb...ML/002086.html

-Jon
 
  #7  
Old 03-28-06, 11:02 AM
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Thanks for all your replys. My concrete guy told me he was using fiber mesh (fiberglass reinforcement) in the mix and it didn't require rebar. He stated it's a common practice. He's old school so I hope I'm not being duped.
 
  #8  
Old 03-28-06, 11:40 AM
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Is there a way to check for the "transient voltages" mentioned above? My pool was put in a couple of years ago and, while I haven't had any problems, a co-worker suggested I check for that after I told him which pool guy I used and after he heard me complaining about how much my electrical bill went up.
 
  #9  
Old 03-28-06, 12:35 PM
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Originally Posted by KenC
Is there a way to check for the "transient voltages" mentioned above? My pool was put in a couple of years ago and, while I haven't had any problems, a co-worker suggested I check for that after I told him which pool guy I used...
Hmm. I'd just go around with a multimeter and verify that all the metallic components had zero resistance between metallic components, myself. If there was an instance where someone was feeling a voltage when touching two items, I would measure the voltage between them, and try to determine the source.

Transient voltages are interesting, because the earth itself is akin to a thousand different conductors connecting points A and B. Picture this: draw a straight line between two points. Then, immediately under that line, draw a second in a slight arc under the straight line. Then another, and another, until you have an inverted rainbow-looking thing connecting the two points. That is what electricity looks like, travelling through the earth. There are many different paths to the same point, and the voltage will take them all, seeking it's source.

...and after he heard me complaining about how much my electrical bill went up.
Transient voltage is uninvited voltage passing through. It's not your pool pump is spitting energy into the earth, just to be clear.
 
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