Hot Springs Spa hot tub electrocution

Hello all, I have a older 120v spa that overnight developed a short. The spa is on a cement slab and if I stand on the cement barefooted, I
get a shock like tingling in the fingers. When I turn on the pump, it gets a bit worse. I have a GFCI and tested it with a ground tester and all good. I went one by one and unplugged the heater, the circ pump and then finally the main pump. Still getting a small shock. Any help would be appreciated.
The only thing I have done since yesterday is to add muriatic acid to get my TA down. I added about a cup last night, ran the jets for a few and covered it up.
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fzbuilder wrote:

Well it's not an electrocution yet, electrocution = death by electric shock, but it very well could turn into that, it's good that you've noticed it now.
Usually the cause of this is the heater, but you say you unplugged that. Is there any other hardware in contact with the water?
The first thing I'd check is the grounding. The control cabinet, heater housing, pumps, any metal parts should all be well grounded. Use a continuity meter to check between the ground at the receptacle it plugs into to the pump, heater, etc. If everything is properly grounded, it should not be possible for there to be a potential between the water and the earth.
It also occurred to me that you could have a ground problem with the whole house. If you are barefoot on the ground then you are grounded, I've seen wires corroded or broken off grounding rods, loose lugs service panels, and other faults that can cause the ground system to float. If you suspect this to be the case, you should have an electrician check it out unless you are knowledgeable and comfortable working with such things.
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All very good points.
But the "bottom line" is that there is "leakage" betwen one of the "hots" and the water.
I would suggest that he get a cheap digital VOM. Ground one lead and "probe" with the other to see where you start to see more than 2 or 3 volts.
If you know what you are doing, it doesn't make much difference what point you pick as your reference. If you stick one probe into the nearby soil and find that you household protective ground has double digits volts you can figure out where the loose/missing wire was.
Electricians often aren't trained to do this kind of detective work. (The guys who answer service calls to the electric utility, OTOH, are.) If the OP is smart enough to post here, he should be able to do the necessary probing himself. When he has localized the problem, he can call in the electrician or fix it himeself.
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On Mon, 25 May 2009 11:25:03 -0700 (PDT), fzbuilder

That is why the NEC requires that the concrete be bonded to the metal parts of the spa. I bet yours isn't. "Tingle current" may not actually be the 5ma necessary to trip the GFCI. You should have this investigated. The problem might actually be a "stray voltage" problem in the concrete/earth near the spa. Does the circuit feeding it go underground? Where is the GFCI?
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On May 25, 10:46 pm, snipped-for-privacy@aol.com wrote:

It has a cord running on top of the concrete to a 20amp 120v wall socket in the garage wall. (I have the tub in my garage). I tried to elevate a good portion of the cord to see if that was it, but still has the prob. I did notice that when I took and extention cord to another room in the house, it was still there, but much less.....? Any method I can use with my volt meter for testing? thanks
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fzbuilder wrote:

Well here's what I would do. Locate the ground rod for your house, normally it's not far from the meter base. Attach a wire to it, an extension cord will work in a pinch, and connect that to one probe of your multimeter. Set it to AC Volts and touch the remaining probe to the water, to the metal housing of the pump, control box, ground prong of the receptacle it plugs into, etc. You shouldn't see more than a few volts. You could also drive a metal rod of some sort into the ground near the spa if you don't want to run a wire all the way to wherever your ground rod for the house is. In my area the soil is fairly moist and conductive, but in some areas getting a good ground is much harder.
Another quick test that would be worthwhile is to measure AC Volts between the ground and neutral (wide slot) on the receptacle, again you shouldn't see more than a few volts, the lower the better.
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On May 25, 10:46 pm, snipped-for-privacy@aol.com wrote:

also, the house next door to me recently had a new back deck built and they have a spa.....could that have anything to do with it? If they had electrical work done? Their spa is about 25ft from mine
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On Tue, 26 May 2009 10:30:26 -0700 (PDT), fzbuilder

I doubt the neighbor has anything to do with it. I think I would start by verifying my ground electrode system on the service. You have a difference between "ground" at the spa and "ground" in the concrete. It could be a bad ground rod clamp or something. "Tingle" current can come from a very low voltage gradient when you are talking about bare feet on wet concrete.
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snipped-for-privacy@aol.com wrote:

Is this true of 120V portable spas as well? I've only ever encountered a few of these, but they were entirely self contained. As far as I know, all of the 120V models are of this type.
My own spa is 240V but also a self contained unit. It's an older unit, and the pad is even older than it, and has no provision for grounding the concrete. There is a #8 ground conductor from the ground bus in the main panel to the GFCI disconnect on the outside wall to the control box in the spa which is bonded to the housings of all other electrical items in the unit. I've never had any issues with mine but if there's anything that should be updated safety-wise, I'm not opposed to doing it.
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On Wed, 27 May 2009 19:45:33 -0700, James Sweet

It sounds like your spa is well grounded and if the pad is fairly well grounded (good ground contact) it should be pretty safe but the code since 2005 is that the concrete should be bonded by either the rebar or by a copper wire grid in the concrete and tied to the spa.
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