Ideas needed,,,

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Electrick One said:
We got the power company out to the site, they pulled the jacks on the transformer, and we still have 23 volts at the pool.

This house is located well away from any other houses,there is only one transformer, and they are the only customer on that transformer. (rural setting)

The service is fed from overhead.

Service riser is PVC with 2/0 copper conductors.

My electrician disconnected the ungrounded conductor from the meter base on the line side ,and they disconnected the base from the driven grounding electrode.
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Did you disconnect the service neutral while the service hot conductors were disconnected?

Normally, the PoCo transformer metal can is connected to something like a "ground ball" or a "butt plate" under the pole it is on. The transformer metal can is also bonded to your client's overhead service drop neutral. The transformer metal can is also bonded to the PoCo transmission line neutral that is going along side the lane.

Because of this bond to the transmission neutral, the neighbors over on the surrounding acreages are hard wired to your client. The neighbor's unbalance neutral current can be part of the problem.

Another hypothetical: the 9 kilovolt single wire transmission line energizing the transformer can have a poor connection to the transmission neutral, and a poor connection to the ground under the pole and be using the pool equipotential plane as a SWER (single wire earth return) transmission loop.
 
As stated earlier, we completely disconnected all conductors from the service utility, both grounded and ungrounded conductors were removed from the termination lugs in the meter base, at the same time. Someone ask about the water line coming into the house. It's has PVC coming in, tieing into copper lines. House was originaly on a well fed with copper lines untill county water was supplied. The (now) internal metal water piping is properly bonded to the service.

Even the electrical inspector that came out to the site this afternoon was at a loss. After comming out and seeing the problem, he gave us the OK to reconnect the customer. The voltage was there no matter what. Guess I'll be going out in the morning to see what damage I can do.

And we STILL have 23 volts at the pool :cry:
 
Try using a clamp on amp meter on the grounding conductor at the poles in the area and at any other services in the area.
Don
 
Are there any radio, TV, cell transmission towers in the vacinity?

Are there any alternative power sources on the property?

What is the proximity of the PoCo transformer (assume that it is mounted on a pole) to the pool?
 
You can disconnect all of the utilities and you will still have the same problem. When current flows thru the earth it causes a voltage gradient.
There are different voltage levels in the earth. If you have ever taken you voltmeter an stuck the probes in the dirt you will get a voltage reading. This is the reason the pool's metal structure must be bonded together so that every point in the pool is at the same voltage level. From the discussion it maybe that there is no bonding in this pool. It maybe all fiberglass without a metal structure. The code requires that the metal frame be connected to the electrical system EGC. If this is done and the frame is bonded, the entire pool will then be at the voltage level where the ground rod is driven at the house. I don't mean to infer that additional ground rods should be driven. Below is a discussion of this problem.

http://www.mikeholt.com/mojonewsarc...ay-Pool-Voltage-from-an-Engineer~20040630.php
 
Bob,
The code requires that the metal frame be connected to the electrical system EGC. If this is done and the frame is bonded, ...
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Which often makes the problem worse...this raises the voltage of all of the bonded parts to that of the electrical grounding system. The area around the pool and the water may still be at true (remote) earth potential.
Don
 
Electrick One,
And we STILL have 23 volts at the pool
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That is very high and indicates a heavy current flow through the earth. This is most often seen in areas where the utility has used concentric neutral cable, with out an outer jacket, for the primary distribution system. The neutral corrodes away over time forcing the current through the earth. I would still look at putting a clamp on amp meter on every grounding electrode conductor in the area that you can find, including those on the utility poles. Note this current can travel long distances and it may be impossible to find the actual source.
Don
 
don_resqcapt19 said:
Bob,
The code requires that the metal frame be connected to the electrical system EGC. If this is done and the frame is bonded, ...
Click to expand...
Which often makes the problem worse...this raises the voltage of all of the bonded parts to that of the electrical grounding system. The area around the pool and the water may still be at true (remote) earth potential.
Don
Click to expand...

But isn't the purpose of the equipotential bonding grid to ensure that there is no potential between the pool and it's metal and other nearby parts?

A pool, it's metal deck and it's ladder and slide and everything else could be a thousand volts to some other ground... but if everything around the pool, including the pool is at the same potential there is no hazard.
 
I agree there is a real problem if someone could feel a tingle between the ladder and the water. However, I wonder if anyone has been inclined to try this since you pulled the meter and all the electrical connections. I might suggest trying another meter, preferably a analog meter (the type with a needle and a scale).

I know that stray currents can cause voltage gradients, but, if everything is bonded, getting 23 volts between a ladder and the water that half the ladder is submerged in seems unlikely.

Steve
 
If you are accurately measuring 23v, that is a lot of voltage. I would think there is some kind of Utility primary neutral issue in this neighborhood.
I would contact the Utility... just expect a ton of futility with the utility.
 
But isn't the purpose of the equipotential bonding grid to ensure that there is no potential between the pool and it's metal and other nearby parts?
A pool, it's metal deck and it's ladder and slide and everything else could be a thousand volts to some other ground... but if everything around the pool, including the pool is at the same potential there is no hazard.
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That would be true if the other items were conductive enough to make an equipotential grid. The water and the earth around the pool deck is not conductive enough for this to work. If the pool is concrete and has metallic reinforcing that is bonded, then there should be no problem between the bonded metal parts and the water, but there will still be a problem between the bonded metal parts and the earth around the pool deck. If the pool has non metallic reinforcing or is a plastic pool, there can be voltage between the bonded metal parts and the water.
Don
 
Thanks for all the help. I went out this morning with the old simpson 260 rolltop to check out the situation myself with the help of a couple of my guys. We found the voltage on the metal parts at the pool to be coming from a little used tile shower in a guest bathroom ,with a lead lined stall, and copper water lines in contact with the lead.
I gather, through a chemical reaction of some type, the shower is now a battery putting out 15 volts DC, according to the Simpson 260. I'll post more when I figure just how the voltage was able to get out to the metal pool parts.
 
We checked that too, benaround, As much as I hate to say it, cause at first I didn't believe it myself,,,The lead lined tile shower IS producing the voltage. The voltage must be being produced through a chemical reaction between the grout, the lead and the copper. As absurd as that sounds .
 
Electrick One said:
We checked that too, benaround, As much as I hate to say it, cause at first I didn't believe it myself,,,The lead lined tile shower IS producing the voltage. The voltage must be being produced through a chemical reaction between the grout, the lead and the copper. As absurd as that sounds .
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You mean there is a electrolytic reaction between the lead shower pan and copper water pipes causing a voltage of 23V on the metal at the pool?

How the heck did you find that?
 
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