OK I got a good one for you all.

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  #1  
Old 04-02-07, 10:29 AM
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OK I got a good one for you all.

I hooked up a hot tub for some friends of mine about 6 months ago, then about a month ago I hooked another one up for my brother in law. The difference between the first one and the second one is that on the first one I didn't have a Hot Tub/Spa GFCI box, I just hooked it up and then last week they finally got the right box and I installed it. But before hooking it up the right way, if you stood bare feet on the concrete and touched the water you would get a tingle, so my first thought was that I needed to get a GFCI between the tub and the panel, of which I did last Friday. However it is still lightly shocking you if you take off your shoes and touch the water. Here is the weird part, I tried to isolate the problem thinking maybe the light or the heater or one of the pumps were going bad, so I unhooked each of the components one at a time, and nothing got rid of the shock. So I turned off the GFCI and it still would bit you with bare feet on the concrete and touching the water. I was like what? This hot tub is fed from a garage panel (new Square D) from the house. Installed 4 years ago, as a 90 amp. So I thought OK let's cut power to the house completely. We shut off the main 200 amp panel breaker and were still getting shocked. There is no other power coming into this house. I called an electrician that had worked with my step dad for over 20 years and he said it might be a bad ground. So I did two things. I installed 2 new 8 ft ground rods by the single existing one and also tightened every ground and neutral screw in the panel including the main neutral. But we are still getting the shock. I measured it with my digital meter from a wet spot on the concrete to the water in the tub and are getting a constant 7 volts. And that's with the whole house dead. So my question is what could be causing this? The electrician said that sometimes situations a house down the block could be bleeding power into a neutral or ground situation. How can I find out where this is coming from if it is indeed the problem? Any thoughts? Sorry for the long post. Thanks.
 
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  #2  
Old 04-02-07, 10:41 AM
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One word of caution. Unless you are a licensed and bonded electrician you should not be doing this work period. Helping your friends and relatives is one thing. Doing it for them sets you up for all kinds of liability and is generally not a smart thing to do.

Installing a hot tub with no GFCI was a very unwise thing to do. Should someone have been electrocuted because of this it would be your fault.

Are the tub and all the metal pieces of equipment properly bonded? Is the electrical panel properly bonded to the incoming/building water pipes?

Yes, a bad neutral connection on a neighbors house could be the problem. You can have the electric company investigate.

One more comment. Your post would be much easier to read if you had broken it into paragraphs. I will give you credit, at least you used capitalization and punctuation which some people seem to forget.
 
  #3  
Old 04-02-07, 10:45 AM
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Yes its all grounded and bonded, and yes I realize there is liability in helping others. But as far as the licensed part, no I might no be licensed but I have over 20 years experience in the electrical trade. Could the meter be bleeding across? I'm going to get a hold of the PUD here and see what they say. Thanks for your comment.
 
  #4  
Old 04-02-07, 10:50 AM
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The current is likely entering from a neighbor's house and returning to the utility via the ground and then the neutral from your friend's house.
 
  #5  
Old 04-02-07, 11:54 AM
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As you have discovered, working on pools and hot-tubs presents risks and issues that you generally don't find in the home. In addition to th liability issues that racraft discussed, the combination of water and electricity can expose subtle flaws in the electrical system that would otherwise go un-noticed.

In the case of getting a tingle by the hot tub, with power totally off to the house, what you have discovered the hard way is the problem of 'stray voltage' and the reason for the 'equipotential bonding requirements' placed in the code. Essentially what has happened is that the water in the hot tub is at the same 'voltage' as the ground wires in your house, which are at the same voltage as the grounding electrodes in the soil. The problem is that the hot tub is sitting on a different patch of soil, at some distance from the ground rods, and this soil is at a slightly different voltage.

This 'stray voltage' can be caused by current flowing in the soil from a neighbor; it can even be caused by the _normal_ operation of the POCO distribution network.

The code mandated solution to this problem is an 'equipotential bonding grid' installed in the concrete pad or soil under the hot tub. This is electrically connected to the hot tub, so that the surrounding ground and the water are all at the same voltage. The details of this are beyond my knowledge to explain properly, since I've never had to deal with it myself; this is why we generally recommend having a professional electrician involved in pool and hot tub installations.

Read NEC article 680, and do a google search for "680.28 hot tub" for several discussions on this topic.

-Jon
 
  #6  
Old 04-02-07, 12:19 PM
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Thanks Jon and Bob, I had the meter pulled at lunch time, and the guy from PUD said about 40 miles north of town there is another situation similar, but they haven't found the source yet. I will look into this 'equipotential bonding grid' and see what can be done. But I'm surprised that this isn't more common than it is. I mean Hundreds of hot tubs are being installed everyday in this country and there has to be a solution. And as far as having a qualified electrician, I have seen some not so qualified electricians, so a piece of paper in your wallet is great but it doesn't tell the whole story. I have called three and they don't have a clue as to what is causing this, and also haven't suggested any type of bonding like you talked about. So I really appreciate your help on this one. Looks like I need to do some more research. Thanks again for your posts. Forums are great.
 

Last edited by DIYaddict; 04-04-07 at 09:25 AM. Reason: Unncecessary quote removed
  #7  
Old 04-02-07, 12:31 PM
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Thumbs up

Reading 680 as we speak, very interesting. Its more common than I thought. The NEC is being revised or has been revised already, thanks again for turning me onto this. You never stop learning. I'm going to print it out and do some heavy duty reading and research, and I have also decided thanks to your reminders not to do any more work for friends. I have been wiring pole buildings and small jobs even though all these years I didn't want to. Not because I don't know how to do it right, but the liability is too great. And its not like I need the money, I just get pressured into helping out people in a small town. I wired my first house when I was 16 (42 now) and my step dad, (Licensed for 25 years) inspected it and he only found one thing wrong, not bad I guess, but maybe its time to quit while I'm ahead. I had 5000 hrs in an apprenticeship program back in 1985 but when I moved back to my small town there was nobody to work under to finish the program. But no regrets, I have a great State job with benefits. Thanks again guys, I'll try and post if I find the answer.
 
  #8  
Old 04-02-07, 12:34 PM
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Another good reference.
http://www.erico.com/public/library/fep/LT1242.pdf
 
  #9  
Old 04-02-07, 07:27 PM
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Wink Always remember...

"No good deed goes unpunished" Pick them very carefully.
 
  #10  
Old 04-04-07, 07:38 AM
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If the underground water piping in this neighborhood is made of metal, there is more than likely a metallic path between each of the houses.

Since the (metal) plumbing at each house should be bonded to the electrical (ground) system) at that house.....

If a house down the street has a loose or corroded connection on their service ground (power company line from the pole or in the meter base), it could be that their (another house) system is using your water line bond to conduct current back to the source (power company transformer).

In other words, their unbalanced current (neutral) is traveling thru your plumbing to get back to the source.

When you stand on concrete and touch the water you are giving the return current another path to get back to the transformer....thru you to the earth.

A properly installed Ground fault device would prevent this from happening.

As racraft said, this is a dangerous situation.
You should never install any type of bath-tub, whirlpool, etc. without GFI protection on the electrical supply to the tub....someone's life may depend on it.

Just a opinion
steve
 
  #11  
Old 04-04-07, 07:46 AM
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Hey Steve, thanks for the reply, it is on a GFCI breaker now, its properly wired. The problem is that there is not enough of a current to trip the thing. I think from what I've been reading and from this forum, I need to add a ground close to the hot tub. Perhaps even a grounding grid. Thanks again. I also think that the reason they never felt this before, is that we have had a really heavy rain season, and thus the path is going to travel better, and the ground system becomes less effective. I have a fire panel at work that every time it rains for 3-4 days straight it gets a ground fault. As soon as the ground drains a little, dries a little, it goes away. We get pretty heavy rain here in Western Washington. I'll let you guys know what I find out.
 
  #12  
Old 04-04-07, 12:05 PM
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The fire alarm "ground fault" has nothing to do with your topic.
This trouble is caused by water in an outside device (horn,light, annunciator etc) or water in a conduit and a nicked wire. Don't confuse the two.

The pool issue can be fatal. Fire alarm issue is a nuisance.
 
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