pool water

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lmchenry

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In the 08 we are required to bond the pool water because of potential difference. What might cause a potential difference? Say from the water to the concrete deck.
 
The potential difference may be from any metallic object and the pool water. Notice that the bonding may be done with the ladder if it has enough square inches in contact with the water. :)
 
One possible reason for bonding the water where there are no metallic items in contact with the water is to make sure that the GFCI will trip if a two wire appliance or cord would end up in the water. If there is no bond to the water it is possible for a hazardous voltage gradient to exist in the water and the GFCI may not trip with out the water being bonded.
 
Is bonding in this way really effective? I'm wondering if the water is an adequate enough conductor to drain sufficiently (no punn intended).
 
The 1/2" by 8' rod would be a little over 15 square inches.

In my opinion, the best way is to install a section of metal piping in the pool water circulation system and bond that pipe. I don't see anything that says the bond has to be in the pool itself, the rule only requires that the metal be in contact with the pool water.
 
Don, that is exactly how I had the last pool that I looked at done. He had no metal stairs or railings, so he put in a 18" pc of metal in his circ. line and bonded it.
 
Is it possible to have a small difference from the deck to the water under normal conditions? Say 6 - 8 volts.
 
lmchenry said:
Is it possible to have a small difference from the deck to the water under normal conditions? Say 6 - 8 volts.
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if there is strayvoltage in the area then yes it is. im actually doing a pool this weekend. ill try to take pictures and post them for you people to see
 
Why do I get the feeling that we will be potentially extensionally equipotencially bonding a whole lot of areas yet to be decided

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[FONT=Arial, Helvetica, sans-serif]Grounding the pool doesn't get rid of this voltage (It's already grounded) because the earth is not a super-conductor. All grounding will do will be to create a potential gradient on the soil around the ground rod. The thing to be aware of here is that the pool will be a certain number of volts above the earth. [/FONT]

[FONT=Arial, Helvetica, sans-serif]Will this potential gradient ever be in a location where barefoot swimmers could access it? For example, with one foot on the soil outside the deck and one foot on the deck? Something to consider when you build your next pool[/FONT]
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[/FONT][FONT=Arial, Helvetica, sans-serif]. [/FONT]

I would have added wet before the word swimmers...at some point you will step from the masked area
 
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M. D. said:
I would have added wet before the word swimmers...at some point you will step from the masked area
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If there is voltage or current in the earth, then there will a potential when you step off the bonded area, however, under most cases this is not a big issue. A few volts between the water and the deck can be enough to cause serious issues for someone in the water trying to get out. The same voltage between the edge of the bonded deck and the area next to it is not likely to cause a problem.
 
I came up with a bonding plate that will be easy and cost affective to use.
The bonding plate is made of stainless steel 3"x 4" witch is 12 square inches and the plate has a threaded stainless steel stud. This fits in the skimmer of the pool, all pools have skimmers. you drill a 1/4 inch hole in skimmer so the threaded stud can go through to the outside of skimmer to have a bonding lug attached to it.
 
Based on an informal test tonight, I want to withdraw my statement that section of metallic pipe will bond the pool water. I even have doubts that 9 square inches of metal in the pool itself will do the job.
 
680.26(C) Pool Water. An intentional bond of a minimum conductive surface area of 5806 mm? (9 in.?) shall be installed in contact with the pool water. This bond shall be permitted to consist of parts that are required to be bonded in 680.26(B).

(B) Bonded Parts. The parts specified in 680.26(B)(1) through (B)(7) shall be bonded together . . .
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In my opinion, this includes a ladder or any other metallic part that is in the water as long as it has 9 in.? :)
 
2.25x2.25=5.06 sq"

2.25x2.25=5.06 sq"

If i need 9 sq" i can use a 2.25 square piece of metal if both sides are exposed ?
 
M. D. said:
Why do I get the feeling that we will be potentially extensionally equipotencially bonding a whole lot of areas yet to be decided
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Who are you, Mary Poppins? :grin:
 
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