Electrical Shock

[South_Texas_Sun]

I agree that wet concrete is a good conductor on the surface, but when concrete gets wet, I could be wrong but I would not expect the moisture to get all the way down to the rebar which is 2-3" below the surface. The concrete surface is somewhat porous but not as much to allow moisture to get down 2". What I could imagine is that when the concrete cracks it could allow some of the moisture to reach the rebar and then it would make a difference.

Mark, in one of my past "lives" I worked in a government building where they would periodically test the concrete conductivity as an indicator for the corrosion to the rebar embedded in the concrete.

As it turns out, much of the world's population housing and the existance of skyscrapers, bridges, and even nuclear power plants, rests on the natural "miracle" of nearly exact coefficents of thermal expansion between rebar and concrete. Move over, Fibonacci.

But what worried me about ....(shading eyes to avoid embarassing direct eye contact of thread-hijacking complaints)......dsamples VINYL pool problem was that his vinyl liner is possibly masking some greater electrical fault that would normally trip a breaker, but doesn't because of the insulation-to-ground properties of the vinyl liner.

I'm not an electrician, but I would imagine that the newly required NEC "grid" requirements mentioned by John are a response to some poor soul's accidental electrocution by a situation very similar to dsamples current dilemma.

I hope it gets fixed, if only for the peace of mind.

STS

[haze_1956]

From original post -

When I disconnect the bond wire from the pump lug, the shock goes away, but there is a potential difference of 4.5vac between the pump case and the bond wire.

If I understand this correctly,

The pool is being enegized with a 4.5 vac current running from the pump case to the pool via the bonding wires. Then when the pavers are touched, the current grounds and gives a shock. Hence the code requirement for a bonded grid below the pavers.

Might running a bonded wire below ground, around the entire outer perimeter of the pavers work?

[Poconos]

Wow, what an interesting thread. Funny too in a way. In the electronics world we don't consider concrete a conductor but yes...you can get shocked bad given the right conditions. Cracks me up sometimes when I go into an electrical supply store and they start rattling off 100 amp wire etc.....I know what I want...Ohms law tells me that. Not criticizing Electricians or the professon but there are those that just follow codes and those that understand the theory. Never read the full NEC but some of the rules don't make sense.
An interesting exercise for those in an urban or suburban location is to take a clamp-on ampmeter and measure currents on water pipe entrances, ground lines off power poles, phone grounds, and anything else you can find. You can totally disconnect your house by dumping the two hots and still find potential differences and currents. BIG difference in rural areas with large distances between sources and many fewer problems.
Someone commented about degrees....from what I've observed in the industry, an engineer is degreed. we all know the definitions:
BS -- Bull ****
MS -- More ****
PhD -- Piled Higher and Deeper.

I'm full of Bull from the place voted the ugliest campus in the U.S. on a Princeton survey per the national news in the last couple days.

I needed some humor today.
Al

[South_Texas_Sun]

Wow, what an interesting thread. Funny too in a way. In the electronics world we don't consider concrete a conductor but yes...you can get shocked bad given the right conditions. Cracks me up sometimes when I go into an electrical supply store and they start rattling off 100 amp wire etc.....I know what I want...Ohms law tells me that. Not criticizing Electricians or the professon but there are those that just follow codes and those that understand the theory. Never read the full NEC but some of the rules don't make sense.
An interesting exercise for those in an urban or suburban location is to take a clamp-on ampmeter and measure currents on water pipe entrances, ground lines off power poles, phone grounds, and anything else you can find. You can totally disconnect your house by dumping the two hots and still find potential differences and currents. BIG difference in rural areas with large distances between sources and many fewer problems.
Someone commented about degrees....from what I've observed in the industry, an engineer is degreed. we all know the definitions:
BS -- Bull ****
MS -- More ****
PhD -- Piled Higher and Deeper.

I'm full of Bull from the place voted the ugliest campus in the U.S. on a Princeton survey per the national news in the last couple days.

I needed some humor today.
Al

I graduated from "Durvee Tech" as we used to call it, in 1974....the first of 3 degrees. Back then we used slide rules instead of calculators for trig functions because the 4 banger calculators wouldn't do sin, cos, tan etc, and besides.......the instructors (correctly, I feel) thought that doing the powers of 10 in your head left less room for error. You actually had to THINK about the (im)probability of your numbers. My dad had a this huge Tektronix storage o'scope that did a paper strip chart of 30 seconds worth of 1 channel data. I used it to get myself hired as a TV tech to put myself through school.

FF to now......I can't do math anymore because I lost my HP in the RV at the river. And I can't read the tiny printing (because of multiple language instruction manuals) of my other calculator, so I just use it as a four banger. Everything else is software.

The Tektronix is a family "heirloom", permanently awaiting long-discontinued tubes, while my Fluke DSO (that can be held with one hand while talking on a cell phone at the same time) has a hall-effect DC current clamp accessory that will run a 24 hour strip chart and let me see an AC+DC waveform and display peak and "lo" RMS or instantaneous transient values. Like you mentioned (Al) it's suprising how durable today's gadgets are, given the vagaries of local power utilities and their aging infrastructure. Our line freqs aren't even constant out here. (Tx hill country)

Everything has changed except the time it takes to get finished with work.The only thing I can think of that is pretty much the same, then as now, is the fun of going swimming.

STS

[JohnT]

dsamples VINYL pool problem was that his vinyl liner is possibly masking some greater electrical fault that would normally trip a breaker, but doesn't because of the insulation-to-ground properties of the vinyl liner.

There has been a move to add a requirement to code to put a plate in the pool for vinyl and fiberglass pools to bond the water. It has been rejected so far because there isn't an agreement on the need, and the size requirements etc. are unknown due to the variety of water conditions and pool sizes. Realistically, the ladder SHOULD function as a bonding electrode for the water, and any current from a household line should clear its ground fault via the ladder--bond wire--pump housing--panel ground path.
Most of the time, the source of such voltage is the poor neutral wiring practices of the utility, so there is no fault to clear.

[South_Texas_Sun]

There has been a move to add a requirement to code to put a plate in the pool for vinyl and fiberglass pools to bond the water. It has been rejected so far because there isn't an agreement on the need, and the size requirements etc. are unknown due to the variety of water conditions and pool sizes. Realistically, the ladder SHOULD function as a bonding electrode for the water, and any current from a household line should clear its ground fault via the ladder--bond wire--pump housing--panel ground path.
Most of the time, the source of such voltage is the poor neutral wiring practices of the utility, so there is no fault to clear.

Ladder?????

(slapping forehead)......I knew our new pool was missing something!

[JohnT]

How do I get the electrical issue fixed?
What steps do I have an electrician/engineer follow to find the problem with our pool? No rebar or wire was put in our concrete decking before or during the pouring of the concrete. The ground wires are in the couping as far as I know.
How do you get a non-responsive pool company to fix the problem?
HELP, Please!
I do live in a rural area. The pool is vinyl 20x40. Mineral Springs system. Sand filter.

Gayle, you are in a difficult situation. The power company may be able to help with the stray voltage, if the will. Being in a rural area may help in that regard, as they may have some familiarity with stray voltage. As to getting an electrician, good luck. Virtually none of them know anything about pool wiring.

You have two distinct issues that probably aren't related. First, you have a stray voltage issue with your property. Second, your pool installation wasn't properly bonded. If you didn't have both, you wouldn't be aware of either.
Fixing the stray voltage problem won't make your pool any safer, just less annoying. Normally, the low level voltage isn't a safety threat, although if you don't know the source, you can't be sure. The real safety issue is the bonding problem. As easily as it allows the stray voltage to be felt, it could allow you to be electrocuted if something like a backhoe or TV tower or grain auger were to touch a power line and the ground at the same time while someone was in the pool.
The only solution is to connect the deck and the metal of the pool together electrically. There is just no easy way once the concrete is in. If it were my pool, I would consider boring into the concrete from the outside edge to where you can hammer in pieces of rebar horizontally every few feet, and connect the ends with #8 wire and connect that to the bonding wire. I don't think that would meet code, but it might fix it. You'd probably have to dig holes so you could get the drill in place.

Good luck.

[hsdancer]

Thanks for all the feedback. I have not gotten a chance to do any troubleshooting in the past several days, but I thought that I would provide a little more information about the pool and its surroundings:


-We live in southern Maryland on 6.5 acres at the end of the road.
-All of the power lines are underground and we are the last house one the line. Basically, we are the last house on a ridge line and the electircal transformer is 300 ft away from the house, on the opposite side of the pool. On the other side of the ridge is a horse farm.
-Our closest neighbor is more than 800 ft away and our house lies between the pool and our neighbor's house.
-There are no power poles or electical lines through our property, or anywhere within sight.
-We have a well between the house and the pool.
-We have no ladder or handrail in the pool, so there is no metal connection between the pool water and the bonding wire that runs around the pool. The coping does not come in contact with the pool water either. Basically, the pool water is insulated by the liner.
-All piping is 3" PVC; we have 3 aqua-genie's and no drain.
-The bonding wire lies in sand/dirt/compacted gravel as it travels around the pool and into the pool house where it connects to the pump lug; the bonding wire is about 180' in length and connects to the aluminum coping every 18"-24".
-The pool is a liner pool with polymer walls. The bottom is vermiculite/ cement (upon which the liner rests).
-The coping is "C" coping and the pool has a 6" wide and 6" deep concrete (w/fiberglass) collar around the top with no rebar.
-The pavers are level with this concrete, and sit on a bed of sand and 6" of compacted CR6.
-The pool is L shaped 44'x20' & 36'x16'.
-The pool has a Salt water generator (220vac) which is connected in parallel with the Hayward pump (2hp), wired for 220vac, i.e., both are on the same ckt breaker and swithed on together. There is no timer.
-My understanding is that the only way the copper bonding loop ever connects electrically to the pool water is through the pool pump.

I will try to attach a picture of the set up (no luck).

Again thanks for all the help. I will be performing a few more measurements this weekend to see if I can isolate the problem. I thought that the 180' of bonding wire would also serve as a ground, but since it lies mostly in sand, that may not be the case. I like the idea of a second bonding loop and an additional copper ground....

[JohnT]

-We have a well between the house and the pool.

-We have no ladder or handrail in the pool, so there is no metal connection between the pool water and the bonding wire that runs around the pool. The coping does not come in contact with the pool water either. Basically, the pool water is insulated by the liner.

-The pool has a Salt water generator (220vac) which is connected in parallel with the Hayward pump (2hp), wired for 220vac, i.e., both are on the same ckt breaker and swithed on together. There is no timer.

-My understanding is that the only way the copper bonding loop ever connects electrically to the pool water is through the pool pump.

I extracted a few things that might be worth thinking about:

Wells can contribute to stray voltage issues if they have any wiring issues. Sometimes they are wired by people who aren't electricians.

Your pool is somewhat unique in that your water is truly insulated from everything by the polymer walls and lack of a ladder.

Is your SWCG connected to the bonding system? This is a system designed to electrically contact pool water, so it could be a source.

The water should never come into contact with the electrical system ground via the pump unless there is a seal failure in the pump.


When you pull the bond wire from the pump case, barring a leaking pump, you are only disconnecting the pool bonding from your electrical system ground. It would appear that in your case, your bond wire is actually energizing your paver decking. That's not too surprising since you are somewhat remote. Your utility's service is probably poorly wired allowing significant difference between the ground and neutral.

Based on what you've said, I have to assume you don't have a light in the pool either, as this would tend to bond the water as well. If you do have a light, I'd bet it isn't bonded.

[hsdancer]

I forgot. I do have a niche light (wet) and it is connected to the same bonding loop around the pool, so the pool water is electrically connected to the bond wire.