Voltage in the Pool

dianedebuda

Gold Supporter
Jan 2, 2018
409
Austin TX
Have been following your saga from the beginning. Glad you were finally able to find a pool knowledgeable electrician and idenitified the problem. Hopefully the power company will do the right thing ... and soon.

Please post what your electrician suggests for retrofit bonding if you continue down that path. I also have a non-bonded pool. :(
 
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Flintstone55

Member
Mar 18, 2020
24
Baton Rouge, Louisiana
Thanks for the update.

Send a letter with that explanation and a link to this thread to the CEO and corporate offices of the electric company. If you don't hear from them after 30 days send it to the officials in your State public utility commission.

Your problem is clear to anyone one understands electrical wiring. The key is that the CB does not disconnect the neutral of a 120V circuit.
Great idea!!!
 

JamesW

TFP Expert
Mar 2, 2011
20,821
I also noticed that my workshop and house have a problem with lights constantly dimming.
This video can explain why the lights change intensity.



These show how the voltage going to your 120 volt loads can become erratic if the loads on the two hot legs are not balanced and there is no neutral or a bad neutral.

Maybe get some monitors on your lines to measure the 120 volt circuits to see if they are the same voltage or different voltages.

If the voltages are different, that points to an open or compromised neutral. Here is a plug in meter that you can leave plugged in to monitor the voltage. The voltage from one leg to neutral should be about the same as the voltage from the other leg to neutral and both should be about half of the reading between the two hot legs.


The more unbalanced the loads on the hot legs, the more the voltage will be different between different legs.

If a neighbor has an open neutral, their neutral current can travel through their ground rod to your ground rod and then through your neutral back to the transformer.

Have your electrician check for voltage and current on the panel ground.
 
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mguzzy

Gold Supporter
Jul 8, 2015
2,336
OV, CA
Meanwhile, I'm running "dirty electricity" and the life span of my electronics are likely shortening before my very eyes, but until I can convince the power company of that, I am out of luck
GREAT write up!... Until they get it fixed I would protect your electronics from the "dirty electricity" with UPS (Uninterruptible Power Supplies) units on each one. Cheap insurance for your PC's and flat panel monitor displays.
 
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JamesW

TFP Expert
Mar 2, 2011
20,821
When you have two identical 120 volt loads, you can connect them in series and run them on 240 volts.

This is what happens in a single speed pump motor that can take 120 or 240 volts. The motor has two identical 120 volt windings. When using 120 volts, the windings are put in parallel by the voltage selector. When using 240 volts, the windings are put in series by the voltage selector.

The problem happens when the loads are unbalanced and try to share 240 in series.

Unbalanced loads share the voltage unequally. One load will get excessive voltage and the other load will get under voltage. This is what happens in a home with no neutral. The voltage fluctuates based on the load balance.

If there is no neutral, all 120 volt appliances on one leg are in parallel and the two parallel sets are in series. As you can see from the videos, the voltages can get pretty erratic when this happens.

Because the home neutral and the transformer neutral are both grounded, some of the current will go from the home ground to the transformer ground to reach the transformer neutral.

You can also have neighbor current going back to the transformer through the ground or from your ground to the neighbor’s ground to their neutral.

If your pool is in the path the current travels to get back to neutral, you’re going to get noticeable voltage even with a bond grid due to voltage drop due to current flowing through a resistance.
 

JamesW

TFP Expert
Mar 2, 2011
20,821
Note: Do not do this yourself.

Have an electrician review the procedure and only do it if they think that it is a good idea and they can do it safely and correctly.

Here is a test you can have an electrician do.

1) Turn off all circuit breakers except one 120 volt breaker.

2) Measure the voltage from the breaker hot leg to neutral. Keep the volt meter connected.

2) Put a 120 volt load directly on that circuit breaker hot to neutral. The higher the better without overloading the breaker. Measure the current and the voltage

3) The voltage should remain relatively constant.

4) Measure for any current going through the ground wire.

5) Disconnect the ground from the panel and measure for voltage between the ground and the neutral. This is dangerous, that’s why an electrician needs to do it.

6) Watch the voltage and current to see if they change.

Basically, you’re load testing the neutral from the panel to the transformer to see if it can support a load without dropping voltage. If the voltage isn't right with no load, there's a problem. If the voltage drops a lot under load, there's a problem. If the voltage or current drop when the main ground is disconnected, there's a problem. If you have current going through the ground wire while it's connected, there's a problem.

When you have both hot legs with 120 volt loads and no neutral from the breaker panel to the transformer, the 120 volt loads are connected in series by the neutral wires from each load to the same neutral bus bar. So, the two hot legs carry the current.

However, if one hot leg is disconnected, the current can only return through the neutral to the transformer or through the neutral to the ground in the panel to the ground rod to the transformer ground rod to the transformer neutral.

BY doing the test, you can see if the neutral is disconnected or compromised.

Note: Do not do this yourself. Have an electrician review the procedure and only do it if they think that it is a good idea and they can do it safely and correctly.
 
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Flintstone55

Member
Mar 18, 2020
24
Baton Rouge, Louisiana
My thanks to everyone for their comments and the education on this. I'm a fan of YouTube-learning, so the video links are also much appreciated. I've learned a lot more about my home's electricity and swimming pools in the last couple of months than I have in my 55 years. I do find it helps to understand what's going on....helps to keep it from being a "mysterious plague" that has somehow only targeted me.

I'll keep you all posted, but the next steps are:
  1. Waiting for the power company to put the voltage recorder on my house and *hopefully* conduct a load study on that transformer. But if they "drop the ball" (especially with the load study), then I'll be escalating this through the power company and even within my city town council/mayor.

  2. The electrician is going to be coming back out to "clean up the box" in my workshop. The shop has it's own power line connection to that transformer, and subsequently it's own meter and breaker box. The box has some funky breakers -- it used to be a laundrymat/washateria, so there are weird sized amperages (one is a 60amp) in the box. The wiring which is exposed and needs to be dealt with also looks like a combination of a professional job from the 50's combined with an amateur job done in the 70 or 80's. So when he comes back for that work, he has suggested we get the power company out there at the same time and he and the power guy can test stuff, converse and compare notes.

  3. As to the bonding of the pool, that is a tough one. My deck was laid out in multiple concrete slabs and the electrician is concerned that we don't know whether the rebar was done in multiple unconnected pieces, or in one rebar grid. If one grid, then we can make just a few strategic cuts and make connect to it there, plus use the pool light niche with a copper connection and run the whole thing back to the pool equipment ground. At this point, with a vinyl liner and no metal in or attached to the pool (i.e., no metal pool ladders, and a completely disconnected light -- which I'd like to completely remove and just cap off), the electrical risk in the pool feels low....now stepping out of the pool and on to the concrete (if it were to somehow catch current) could be a problem, I guess.
Anyway, thank you all again....this has been extremely helpful!!!
 
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MITBeta

Well-known member
I had a customer complain that his furnace fan was turning on at all hours and waking him up in the middle of the night, thermostat turned off. No call for heating or cooling. We troubleshot this problem for weeks: changed control boards, 24v transformers, thermostats, etc.

My shop happened to have this gizmo made by Fluke that would monitor and record voltage excursions beyond preset points.

I had this monitor plugged in at my own house for several months and saw 4 minor excursions.

We plugged it in at his house on Friday morning and went back to collect it on Monday. There were 1100 excursions during that time, the most dramatic of which were momentary hits of 200v on a 120v leg as well as 11v between the neutral and ground.

We convinced him to call the electric company, which promptly sent a tech who found a broken neutral at the pole. We tried to convince the customer that he was lucky that none of his other electronics or equipment were fried. Never did get a thank you.