Tingle in swimming pool - Contractor Talk - Professional Construction and Remodeling Forum

wraiths · 07-26-2007, 05:51 PM

Got a call from one of my customers I do alot of work for he said when getting out of his pool an he grabs the handrail he feels a slight shock. His pool is probably 18 years old an he has never felt it before, He told me his pump is hardwired an the pool has an underwater light got any ideas what it could be or if any of you all have run into this before? Thanks

mdshunk · 07-26-2007, 06:47 PM

Yeah, I'm betting the bond wire to the handrail or the deck re-wire rotted off. Get your ohm meter and check the continuity between everything metal around.... wet niche, deck box, pump lug, stair rail, diving board, etc. If you happen to own a DLRO, that would be even better to use than the ohm meter. If you own a megger, might not hurt to megger the pump out, to see if the windings are "leaking" to ground, but if the bonding is properly done, this wouldn't matter anyhow. It's a bonding issue. There's a break in the equipotential plane someplace or perhaps several places. It's even possible that it was never done in the first place.

wraiths · 07-26-2007, 06:55 PM

Kinda what I was thinking but one question how to fix it if the bond is broken going to the handrail . You cut the cement up hehe.... More seriously i am ashamed to say I have a megger an have never used it, not sure what to look for in the readings? Remember back years ago doing industrial work just learning seeing my mentor use one but it wasnt very often, mainly at that time I was the gopher. Maybe a short lesson on what readings I should see when meggering a 240V pool pump an what to look for.

mdshunk · 07-26-2007, 07:06 PM

Quote:

Originally Posted by wraiths

Kinda what I was thinking but one question how to fix it if the bond is broken going to the handrail . You cut the cement up hehe....

I guess so. I think it's beyond what an electrician should fool around with. Do your testing, have them hire a pool guy to effect the demolition, you do the bonding, and have the pool guy put it back together.

wraiths · 07-26-2007, 08:28 PM

Hey MD how bout a short lesson what the readings should be or what I should look for when megging a 240v pool pump motor? Thanks

mdshunk · 07-26-2007, 08:36 PM

Quote:

Originally Posted by wraiths

Hey MD how bout a short lesson what the readings should be or what I should look for when megging a 240v pool pump motor? Thanks

Do not megger line to line, or you might blow up good winding insulation.

Megger from each line (or neutral) to the pump body or pump lug. You should read greater than 20 megohms from any terminal to the metal pump body. Simple as that. If you get lower than 20 meg, the pump is on it's way out. Less than 10 meg, and the pump is trash even if it still runs.

Magnettica · 07-26-2007, 09:32 PM

Also, if you have an ohmmeter it should read OL (open line) from the motor windings to the equipment ground. Or if you only have a continuity tester there should be NO continuity from windings to ground. "Tingling" around the pool is definitely an NEC violation. I would tell whoever owns the pool to start all over and do it right. Someone could easily be killed in this situtation.

Good luck!

Magnettica · 07-30-2007, 09:30 PM

Got an update on this pool situation?

POOLMANinCT · 07-30-2007, 09:52 PM

i bet there is "patch" ini the concrete over a plumbing repair, demo saw right through the #8......

how the theory md?

POOLMANinCT · 07-30-2007, 09:56 PM

oops i jumped the gun & didnt read above

mdshunk · 07-31-2007, 06:25 PM

Quote:

Originally Posted by POOLMANinCT

i bet there is "patch" ini the concrete over a plumbing repair, demo saw right through the #8......

how the theory md?

Could very well be.

I most often find that the bonding was done with a terminal or connector that was never really meant to be put underground and in concrete. Guys seemed to use whatver was handy, back when. I mostly find the connection rotted off someplaces, due to this. Could also be an old repair cut the bugger right off. Hard to say.

wraiths · 07-31-2007, 07:53 PM

The update lets see ...... The handrail had about 2 volts on it. It was no longer bonded . I couldnt find where it was coming from so I disconnected power to the house at the meter an the tingle was still there started thinking it had to be coming from the utility lines . Called the power company to come out an check it as of yet still waiting for an answer. Talked to a retired power company man an he said it used to happen alot said it may take days to find where it is coming from. What do you all think?

mdshunk · 07-31-2007, 08:51 PM

Quote:

Originally Posted by wraiths

The update lets see ...... The handrail had about 2 volts on it. It was no longer bonded . I couldnt find where it was coming from so I disconnected power to the house at the meter an the tingle was still there started thinking it had to be coming from the utility lines . Called the power company to come out an check it as of yet still waiting for an answer. Talked to a retired power company man an he said it used to happen alot said it may take days to find where it is coming from. What do you all think?

It will always have voltage on it to some extent. That's why we do pool bonding. Don't worry about where it's coming from. Just get the bonding right, and nobody will get hurt. As long as we have ground rods and water pipe grounds at houses, Kirchoff's law will prevail. There will always be some voltage going through the earth. It's not a utility problem. It's a pool bonding problem.

Magnettica · 08-01-2007, 10:25 PM

Is this pool set beneath utility power lines?

If yes, 680.8 Overhead Conductor Clearances.

wraiths · 08-04-2007, 11:04 AM

Well guys the customer called back an told me that the power co. told him that it wasnt enough to hurt any one an that he didnt need to rebond the rail. They told him to just wet down the cement when there swimming an not to worry bout it. He opted not to get me to bond the rail ....Cant believe they said that I wouldnt want my kids in that pool with it like that. Anyway thought I would let you know...

BuildingHomes · 08-04-2007, 11:24 AM

Quote:

Originally Posted by wraiths

Cant believe they said that I wouldnt want my kids in that pool with it like that. Anyway thought I would let you know...

Then maybe send him a letter reviewing that phone conversation and also state your recommendations. Cover your ass just in case that voltage goes up a bunch on the day they forget to water down the deck.

JohnJ0906 · 08-05-2007, 09:05 AM

Quote:

Originally Posted by BuildingHomes

Then maybe send him a letter reviewing that phone conversation and also state your recommendations. Cover your ass just in case that voltage goes up a bunch on the day they forget to water down the deck.

I want to second this. CYA.

I can't believe a POCO would say that this wasn't dangerous! I agree with Marc - the bonding needs to be checked/fixed

mdshunk · 08-05-2007, 09:10 AM

I happen to agree that the 2 volts is not enough to be significant to the POCO. I'm sure you can measure much higher before it's significant. SOME voltage will always be present at any pool with unbonded metal items and unbonded deck material. This is a perfectly natural thing, which is a law of physics (Kirchoff's law).

The bigger shame in this case is that the people have been told to, and have accecpted the fact that, water is a suitable bonding conductor. Just wet the pool deck down... yeah! It probably does work, but water is not an NEC approved pool bonding conductor. It must be at least #8 copper wire.