ECN Forum Forums Code Related Discussion NEC & other Code issues Pool wiring

In some of the justifications I have seen for the ground mat under the fiberglass pool it was mentioned that they may be somewhat conductive. Although this is a very high resistance it still might be enough to get some stray voltage to the water across the thousands of square feet of material. With all the chjemicals in pool water I bet it is more conductive than you would think.
Some years ago I did some conductivity studies on water in a white bucket with 120v, 1 foot copper probes about a foot apart, a 60w light bulb and a meter. I don't remember all the details but I do know it didn't take many impurities (salt in my test) in the water to light the bulb. Maybe I will get a few minutes some day to do it again with pool water.

I did an experiment years ago, putting 2 ends of a wire in a glass of water and plugged in the other end.. and nothing happened. Not sure of the resistence of water but it does provide a much better path if your wet when getting shocked, because it coats your skin so well.

Could we NOT talk about doing electrical experiments with water? There might be some serious safety issues involved.

Thanks
Dave

I have to believe we are qualified professionals here who can manage the risks but if it needs to be said

"don't try this at home kids"

In the test bed I made before there were no exposed conductors and the bucket was closed up before the test was energized so the wet part was not exposed either. (GFCI present etc)

As for that one fiberglass pool, the one that the EC said he never heard of stray voltage, well he learned about it real quick. It seems he was wiring up the wet niche light and got wacked with voltage. I don't remember just how much, but the EC said that he felt it and he KNEW that the pool wasn't even wired yet. That was when I got the call for help with stray voltage. I think he was leaning over the coping working on the wet niche, plus the ground was wet.

Oh, I forgot, the stray voltage doesn't just happen to pools. A friend of mine who is an EC was wiring up a brand new house. The homeowner complained that when he touched the hose bib and he was barefoot, he got a shock. There was about 15-25 volts from the earth to the hose bib. The EC tried everything, he pulled the meter, the CATV, Telc. Water meter, but nothing worked. We think it was a bad underground wire from the POCO. The whole neighborhood was an UG development with pad mounted transformers.

Had an electrician call me to look at a new pool he was installing.
He said the GFI receptacle kept tripping.
Then he pointed out that the circuit hadn't been connected to the breaker.
Neighbor had a bad neutral that was back feeding to the pool grid.
There is stray voltage out there.
Alan--