chasing stray voltage - need some help

[Cobra6]

I have been chasing stray voltage in my yard for a couple of weeks. All of my neighbors have been getting shocked in their swimming pools - we had about 15V - 35V in the ground at any given time.


I finally found out that when I turn off my circuit with my garage door opener, the voltage in the ground went away. I unplugged the opener, but when I flip the breaker back on, the voltage comes back. I also have 4 regular wall outlets on this circuit.
Since I have isolated the circuit, I am trying figure out what to check on the outlets to see if I have a bad neutral or something.

Any suggestions?
Thanks

 

[mrb]

this voltage in the ground, whats it measured between?

 

[Cobra6]

this voltage in the ground, whats it measured between?

I first measured it by putting one lead on the volt meter in pool water, and one on the handrail.

today, I also plugged an extension cord into an outside outlet, put one lead in the ground, the other in the ground hole in the cord, and measured ~18V

 

[PrecisionTools]

I also have 4 regular wall outlets on this circuit.

Anything plugged into these outlets?

 

[Cobra6]

Anything plugged into these outlets?

Nothing now - I unplugged my garage door opener and a couple of lamps - still had the same problem with everything unplugged

 

[justsam]

What do you measure from the ground on this circuit to the neutral on this circuit? Does it change when you put a heavy load on the circuit?

IF YOU CAN NOT RESOLVE, GET A PRO OUT THERE BEFORE SOMEONE IS HURT!

 

[Aceman]

I'd start by looking for a bad neutral connection at your house or one of your neighbors. I'd do that by looking at the grounding:

Do all the houses have ground wires to their water pipes?

I'd put an amp clamp on that ground wire at every house and see what you come up with.

 

[Mattlt]

Agree on having a pro check it out. But maybe something else to check: Has it been dry in your area? Grounding to wet earth is much better/easier than dry.

I've run into this with poor grounding of electric fence controllers. Simply pouring a pail of water on the ground rod makes a world of difference.

 

[Milton Shaw]

The utility company may be able to come out and find the cause of the problem. You have a bad connection to neutral or hot connected to ground some where. Utility company has ground meters and other aids for them to find problem. They don't want this either.

 

[Cobra6]

The utility company may be able to come out and find the cause of the problem. You have a bad connection to neutral or hot connected to ground some where. Utility company has ground meters and other aids for them to find problem. They don't want this either.

I have had the utility company out there - I think they are baffled and don't want to admit it. I also think I have a bad neutral - possibly from them.
They said that one of my neighbors on my same transformer probably had a water heater with a bad element causing the voltage feedback, but now I know better.

 

[mrb]

is your garage attached or detached?

 

[Cobra6]

is your garage attached or detached?

The garage with the opener and this circuit is attached - I have 4 electrical outlets in my house on the same circuit - I am not sure what to look for in those outlets - I am thinking about checking the ground circuit on each one to see if there is anything there that doesn't add up.

I have not yet hooked up the power to my detached garage, I have been distracted by this for several days.

Nothing really changed (physically) on my system to cause this - I am wondering if a lightning strike did something?

 

[Thruxton]

What do you measure from the ground on this circuit to the neutral on this circuit? Does it change when you put a heavy load on the circuit?

IF YOU CAN NOT RESOLVE, GET A PRO OUT THERE BEFORE SOMEONE IS HURT!

I'm all for DIY, I have installed two panels from the weatherhead down which both passed inspection first go-round. But this is a difficult problem (I have spent mucho time with ground voltage on livestock water troughs, so I have just enough experience to know how complicated it gets). The last line above is, I think, what you should pay attention to. Get POCO back out, get a pro, but don't do it yourself, for the reason justsam states. Especially DON"T DO IT YOURSELF on your neighbors' systems - you really do not want that kind of liability exposure. Ask yourself why licensed electricians (plumbers, etc) are bonded. Don't let them off the hook until the problem is fixed, this is potentially (pun intended) dangerous stuff.

 

[Stuart in MN]

There are some pretty elaborate grounding requirements for swimming pools as well, so the neighbors need to make sure the pools were installed properly.

 

[Cobra6]

There are some pretty elaborate grounding requirements for swimming pools as well, so the neighbors need to make sure the pools were installed properly.

The pools are good - have all been there 5+ years with no problem - I am picking up the voltage in the ground (dirt) - and it goes away when I turn off one breaker in my house -
I just don't really know what to look for in the outlets in that particular circuit without completely rewiring it (which may only fix the symptom and never reveal the real problem)

 

[MrMark]

The way to check requires a clamp meter. You can do two things at your entrance. If you clamp all three current carrying wires, the two hots and the neutral, it should show approximately zero. The magnetic fields of the three wires will cancel each other out.

This shows that all the current is returning on the neutral, as it should. The other test is to clamp each hot wire and record the current. Subtract the phase A current from the phase B current and then account for that current. It should all be on the neutral. If not you need to find where it went, most likely on the ground. Not much should be able to flow on that ground in a proper system - almost nothing really.

Example: Phase A = 25 amps, Phase B = 10 amps, N should = 15 amps and ground should be zero. If you see current on the ground that should be on the neutral, you have found the problem.

If you have metallic water piping for your municipal service and you are not isolated from it by plastic, you are going to have some current on that conductor as well. I wanted to add that. That is normal. What is not normal is appreciable current going through the earth itself in most scenarios.

You also can do a check to see if one of your neighbor's has an issue with a neutral and is putting current through the ground (commonly bonded water piping system or Earth itself) that is coming up into your panel and returning on your neutral. You can shut down completely and clamp your ground to see if any stray neutral current is trying to return through your service neutral.

 

[MrMark]

You are measuring across a big enough resistor to drop 30 volts? You say you are across the water to a hand rail? How are people getting shocked?

Bad shocks? Tickle? When they get in the pool?

This really looks like a POCO issue unless you have a neutral that is somehow making a circuit through the dirt. If that were the case, you would see the problem with the power levels on that circuit.

How does this circuit that you suspect operate? What is the voltage line to neutral on that circuit. What does it drop under load? Plug a hair dryer into that circuit and check the drop on that circuit while the drying is running and get back to us.

 

[Cobra6]

You are measuring across a big enough resistor to drop 30 volts? You say you are across the water to a hand rail? How are people getting shocked?

Bad shocks? Tickle? When they get in the pool?

If you are in the water and touch the metal handrail or metal molding (that holds the liner) - you get a shock -
about 25V - 30V - enough to get your attention. I checked some days and it is 10V - 12V or a tingle.

I will see if I can try some of the other things and get back.

 

[nehog]

Maybe disconnect the pump(s) and the in-pool lights too...

 

[Cobra6]

Maybe disconnect the pump(s) and the in-pool lights too...

That was the first thing I did .......... I figured that was the problem, but no dice.

 

[mrb]

is the circuit in question supplied from the main panel or a subpanel? Do you own a clamp on ammeter?

 

[Cobra6]

is the circuit in question supplied from the main panel or a subpanel? Do you own a clamp on ammeter?

it is supplied from the main panel -
I am getting a clamp on ammeter from a friend tomorrow.

 

[mrb]

it is supplied from the main panel -
I am getting a clamp on ammeter from a friend tomorrow.

the circuit you turn off and stop the leakage, how is it grounded? Does it power anything that could have a fault that could leak current either into the soil or an unbonded water pipe?

Is your water piping metal, and if so is it properly bonded?

 

[mrb]

also, are you missing the neutral-ground bond in your system? Describe your system from meter back to the main panel. A couple examples would be "meter on a pole, main breaker panel on the house" or "combo meter/main on the outside of the house with a breaker panel inside the house"

 

[Cobra6]

the circuit you turn off and stop the leakage, how is it grounded? Does it power anything that could have a fault that could leak current either into the soil or an unbonded water pipe?

Is your water piping metal, and if so is it properly bonded?

the circuit and panel has a grounding rod outside the garage where the main panel is located. My water piping is metal, but I don't know (not smart enough to know) if it is properly bonded.

There are 6 regular 15A wall outlets on the circuit, one of which had my garage opener plugged into it on the garage ceiling. The other outlets are inside the house and had a floor lamp and couple of table lamps plugged in. Nothing is on there now.

The circuit is on a 20A/20A tandem breaker - I am thinking about changing out the breaker just to see if it changes anything. I just wonder if I would see a voltage drop from one outlet to the next if there was a problem with a particular outlet.

 

[Cobra6]

also, are you missing the neutral-ground bond in your system? Describe your system from meter back to the main panel. A couple examples would be "meter on a pole, main breaker panel on the house" or "combo meter/main on the outside of the house with a breaker panel inside the house"

"combo meter/main on the outside of the house with a breaker panel inside the house"

I have new wiring (went from 3 wire to 4 wire) - upgraded my service from 200A to 400A. I had this problem before I upgraded to 400A service.
I thought I had poor grounding at my pool pump and better grounding would solve the problem, but it didn't really do anything.

I can take pictures of my service boxes tomorrow.

 

[mrb]

do this on both the circuit with the issue and another circuit and report back the results: Take your voltmeter and measure voltage between the neutral (wide slot in a receptacle) and ground. Do this with the problem circuit on and do it with it off.

 

[smike]

If you turn that breaker off and everything is fine, you problem is with that circiut. Is there a old post light or underground wire off that circiut that you know about? Don't know how old you house is. Is there a ground for that circiut? Is it conected at the recepticals? Unplug everything see if you still have a problem. Sounds like sum how that circiut is energizing the ground.
I would start splitting the circiut till you problem goes away to narrow it down.

 

[Cobra6]

I had to work late today, so couldn't run anything down.

There was an addition on the back of my house about 12 years ago - I moved in 10 years ago. House was built in '87.

The circuit does run where the addition is - I am going to check outlets tomorrow as soon as I can sneak away from work.

 

[rkevins]

you could pull all receptacles out and un wire all of them, use a ohm meter to trace how they are connected and make sure there is not a wire going somewhere you did not know of, also check to ground to see if something is shorted. I know this sounds like a lot of work but it sounds like this circuit is the source of the problem

 

[richkl]

In Georgia I have been informed that the electrical code requires GFI outlets around water- sink, bathtub, swimming pool. I agree with the other posters that you should get a liscensed electrician to find and fix the problem.

If you really want to stir up a hornet's nest ask your home insurance agent what you should do about this. And be prepared for some unhappy words.

By the way, how is your liability insurance?

Richard

 

[Racecarl]

I would suggest inspecting every outlet on the opener circuit--perhaps a neutral and a hot wire were miswired.

I had almost finished wiring my detached garage and wanted to use my newly installed lights to finish up work one evening. I did not have power from the pole to my meter installed yet, so I made a pigtail to plug into an extension cord from the house. I connected the black to the hot wire for the lights and the white to the neutral bus in the new garage panel box. I had the panel box grounded with a grounding rod as well as bonded to the rebar in the foundation wall. I plugged the pigtail into the cord and 5 seconds later the breaker in the house tripped that fed my cord. All of my wiring in the garage is in EMT so I thought maybe I pinched a wire in a box. A quick check with my ohmmeter said that the hot wire was in no way connected to the neutral. I even hooked up a megger to the hot wire and found no defects in my garage wiring. I double-checked my pigtail--everything was OK.

The next night I started checking the wiring on the outside outlet on my house. I checked the box that the cord was plugged into and found that some dumba** had the black wire on the silver screw and the white wire on the brass screw. Now I was getting paranoid. I then verified that the black wire in the outlet was indeed supposed to be the feed wire, so I reconnected the outlet properly. I decided to check the rest of the house outdoor outlets. The next one was wrong so I fixed it. The third outlet had a black and white wire on each side(!!!) so I fixed that. I ended up checking every outlet in the house that I did not wire personally but found the rest were wired properly.

It pays to check everything.

 

[Cobra6]

OK -
I checked all of the outlets on the circuit (6) with my voltmeter.
I did this on each of the 6 outlets:

Placed the red, or positive, probe in the smaller of the two slots. Placed the black probe in the larger slot. The voltage was approximately 120 volts AC - went from ~121V in the first outlet on the circuit to ~118V on the one farthest from the main circuit box

Placed the red, or positive, probe in the smaller of the two slots. Placed the black probe in the ground terminal, or the round opening. This gave me the same reading as the regular voltage in the outlet.

Placed the red, or positive, probe in the large slot. Placed the black probe in the ground, terminal or the round opening. This measured 0 volts AC.

I tried to describe exactly what I did and results I got here - but I did not draw any conclusions - everything seemed normal.
What does this eliminate?

I also discovered yesterday that my ADT system was on this circuit - unplugged it, but wondering if the battery or something in there is hooked into something. still chasing this, but I still have (today) about 12.5 V going into the dirt when the circuit breaker is on, 0 V when it is off.

 

[Alchymist]

Sounds like a load (or partial load) isn't finding neutral, and going back to the main panel on the ground wire. (WAG).

 

[Cobra6]

It pays to check everything.

I agree - I am puzzled though because I have no new work on this circuit - it hasn't been touched in 12 years or so.

 

[BillK]

Bari,

Sorry to say it in this manner but . . . . how much longer are you going to be stupid and cheap ????? ...... Until someone gets killed ???????

Call an electrician and tell him to fix it ! Doesnt matter what the cost is, just fix it.

Just my worthless opinon,

 

[MrMark]

You need to do the load test with the hairdryer. You have established baseline voltage levels and everything looks normal. Now plug in the hairdryer and do the exact same test. Check to see how much the line voltage drops under load. This will tell you if you have a neutral path problem. This is the exact same test that the poco would do on the main panel to check their neutral, only they use a device that is essentially 3-4 hairdryers.

An electrician may be able to help but it would have to be a very good one. This would be over the head of most.

 

[Cobra6]

You need to do the load test with the hairdryer. You have established baseline voltage levels and everything looks normal. Now plug in the hairdryer and do the exact same test. Check to see how much the line voltage drops under load. This will tell you if you have a neutral path problem. This is the exact same test that the poco would do on the main panel to check their neutral, only they use a device that is essentially 3-4 hairdryers.

An electrician may be able to help but it would have to be a very good one. This would be over the head of most.

OK - I think I am tracking - I was about to do this with a small quartz 1600W heater - I will see what it does.

 

[MrMark]

That should work well. Make sure you establish a normal drop under load baseline by doing that test on a known normal circuit. This way you will have something to compare against on the drop test. You should only drop a couple volts on this for a good circuit.

Check the dirt drop while you are doing this too. Give us the dirt drop under load and with no load. I think you said you had 12.5 volts with no load. Measure across the exact same spots.

 

[MrMark]

What consumers are on this circuit that are continuous?

You mentioned the "ADT". I don't know what this means. Is this device consuming power all the time?

Can you disconnect this ADT to isolate it from the problem/check to see if the problem goes away without the ADT?