# Voltage on neutral



## Cirus

Ive got an H frame with a single phase 240 volt 1200 amp service and mdp in the middle of a race track. It has 16 double pole 50 amp breakers feeding 16 poles with around a hundred 1000 watt sports lighters. It has a 50 amp 240 volt service feeding restrooms about 500 feet away and 150 amp 240 volt service feeding a concession stand also about 500 feet away. The sports lighters are tapped for 240 volt. Everything is fed underground using 3 wire URD.

Voltage is good and everything works like a charm except when the pole lights are turned on I'm getting around 34 volts on the ground of the 120 volt receptacles. Of course on some of the appliances you get a tingle if you touch the appliance and the concrete with a wet hand. Both buildings have there own subpanels with ground rods at both. Neutrals and grounds are on seperate bars but the bonding jumpers are installled. When jumpers are removed the reading goes back to zero. When the lights are turned off the voltage from the receptacle ground to the wet concrete goes back to zero. If the concretes dry it might read 7 or 8 volts. Turning off the main in the subpanels has no effect. I assume I'm getting a backfeed on the neutral but why? The only 120 volt loads are at the two buildings since the pole lights are 240 volt so neutral load is lite. I've never run into this before and I've dealt with 3 wire 240 volt subfeeds many times with same circumstances. Any ideas?


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## gottspeed

I'm not sure about this specific application but where I come from you pull the bonding jumpers out of sub panels for this exact reason.

I'd like to know why the lights being on or off play into this problem since they are wired phase to phase. Hope someone chimes in.


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## McClary’s Electrical

gottspeed said:


> I'm not sure about this specific application but where I come from you pull the bonding jumpers out of sub panels for this exact reason.
> 
> I'd like to know why the lights being on or off play into this problem since they are wired phase to phase. Hope someone chimes in.


 
Not with a 3 wire feed you don't.


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## Cirus

mcclary's electrical said:


> Not with a 3 wire feed you don't.


Exactly. If I pull the jumpers then you have no ground. The ground rod sure won't clear a fault. The two buildings and service was existing. The service and panel was sized for future lighting when it was installed several years ago. All we did was add the pole lighting. Everything was fine until we added the sports lighters and then its only when they are on. I've never checked it with just a few of the poles on. I assume the reading would be less then 34 volts. Its not enough tingle to make me let go but to someone who knows nothing of electricity its scares the crap out of them. They had been using the lights for some time before they encountered the problem. I can stand in the kitchen with work boots on and wet hands and grab the refrigerator or any other metal framed appliance and get nothing. If I drop to a knee or touch the concrete floor with my hand I get a tingle. The wet hand make the difference. I guess thats why it took a while to show up. The conditions have to be just right.


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## hardworkingstiff

Cirus said:


> Voltage is good and everything works like a charm except when the pole lights are turned on I'm getting around 34 volts on the ground of the 120 volt receptacles.


I'm not sure I understand what you are saying (exactly). Would you answer these questions?

At the receptacles with the pole lights turned on:
1) What is the "hot" to "neutral" voltage reading?
2) What is the "hot" to "ground" voltage reading?
3) What is the "neutral" to "ground" voltage reading?

Edit: These receptacles, where are they located? What are they fed with (wiring)?


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## Cirus

Also, the bonding jumper is installed at the mdp and a ground rod is driven. The pole lighting is the biggest load. When they are off there is vertually no load on the mdp. The restroom has six 8' strips and thats it. The concession is all gas except for a 2 ton a/c unit, 2 refrigerators, ice machine, and misc. lighting. If the mdp was out of balance I might see this happening but every breaker is a double pole. The restrooms have the same problem but no one every noticed it but I just checked it out of curiousity. What little neutral load there is is at the subpanels.


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## Cirus

hardworkingstiff said:


> I'm not sure I understand what you are saying (exactly). Would you answer these questions?
> 
> At the receptacles with the pole lights turned on:
> 1) What is the "hot" to "neutral" voltage reading?
> 2) What is the "hot" to "ground" voltage reading?
> 3) What is the "neutral" to "ground" voltage reading?


1. 116
2. 116
3. maybe 1 volt

With the lights off, at the subpanels I get anywhere from 124-125 phase to neutral and 248-250 phase to phase. With the pole lights on it drops down to about 116/232


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## Cirus

They are located through out the concession and bathroom. They are fed with romex 12-2G. The buildings are wood structures.


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## Big John

When you removed the bonding jumper, did you check to see if you still had continuity between neutral and ground? Have you checked to see if you have current flow on your equipment ground? It sounds like you're neutral is bonded in more than one spot and the EGC is a parallel path.

-John


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## hardworkingstiff

Cirus said:


> 1. 116
> 2. 116
> 3. maybe 1 volt
> 
> With the lights off, at the subpanels I get anywhere from 124-125 phase to neutral and 248-250 phase to phase. With the pole lights on it drops down to about 116/232


Where did the 32 volts in the op come from?

Are you reading that from the ground of the receptacle to concrete? That's with the bonding jumper at the 1st means of disconnect being connected, right (and it's the only place the neutral is referenced to ground?)?


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## McClary’s Electrical

Big John said:


> When you removed the bonding jumper, did you check to see if you still had continuity between neutral and ground? Have you checked to see if you have current flow on your equipment ground? It sounds like you're neutral is bonded in more than one spot and the EGC is a parallel path.
> 
> -John


I agree, but also would like to add it would take your scenario, and a loose grounded conductor on top of it, to put voltage on metal appliances. (that's what I think is happening)

To the op, what are you referencing your meter to when you read the 32 volts on ground?


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## Cirus

Big John said:


> When you removed the bonding jumper, did you check to see if you still had continuity between neutral and ground? Have you checked to see if you have current flow on your equipment ground? It sounds like you're neutral is bonded in more than one spot and the EGC is a parallel path.
> 
> -John


With the jumper installed i get about 34 volts from the neutral bar in the subpanel to the ground rod or wet concrete. The neutral is bonded at the mdp and the subpanels. If I remove the jumper in the subpanels then I have no ground to clear a fault. For right now I decided it was better to get a possible 34 volt tingle opposed to 124 volt jolt if something shorts.


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## A Little Short

When you say the bonding jumper is connected, do you mean from the EGC bar to the can or from the neutral bar to the EGC bar? Is the neutral bar isolated (floating) from the can without a jumper?


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## Big John

Cirus said:


> With the jumper installed i get about 34 volts from the neutral bar in the subpanel to the ground rod....


 Something is wrong there. With the bonding jumper installed, your grounding-electrode should then be directly connected to your neutral bus. You should not be able to read any voltage at all between neutral and the ground-rod.

-John


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## Cirus

The mdp and subpanels cans are both bonded to the neutral


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## Aussielec

Sound's like a high resistance main neutral on you're lighting subpanel.

Also have you taken a continuity reading of you're earthing conductor down to the earth stake?


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## Cirus

Big John said:


> Something is wrong there. With the bonding jumper installed, your grounding-electrode should then be directly connected to your neutral bus. You should not be able to read any voltage at all between neutral and the ground-rod.
> 
> -John


That reading is with the ground wire removed from the ground rod. That is from the neutral bar to the ground rod. The panels are on the outside of the buildings. I've checked from neutral bar to ground rod and from the receptacle ground to wet concrete in the building. About 34 volts with pole lights on.


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## wendon

It sounds to me like you've got a short to ground on one of your feeders. I would shut off each breaker and see when the voltage goes away. Possibly one of the pole lights or the service are shorted to ground. The light could be improperly grounded (or not grounded at all) Could be a host of things. Have you had the POCO check out the primary side? If they have a bad connection or something of the sort, you might be getting return current on the ground rod when you apply the load. Are the services to the pole lights underground or over head?


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## varmit

This sounds like multiple problems:
There is a loose or broken neutral somewhere. Also, any connections between the ground and neutral, intentional or accidental, down stream of the service entrance, need to be eliminated. You say that the circuits are ran in "URD". Is this the two insulated conductor and one bare conductor or all three insulated? 
If some of these 3 wire circuits supply both 230 and 120 VAC loads, the circuit to the building(?) would need to be 4 conductors- 2 hots, N, and GND.

It appears that you have inherited one of the infamous "It's always worked before", even though it was done incorrectly originally.


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## Cirus

The mdp and the lighting panel are one in the same. The lighting breakers and the breakers for the two buildings come from the same panel. Its a 1200 amp raintight main breaker Square D I-Line panel.


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## McClary’s Electrical

Cirus said:


> That reading is with the ground wire removed from the ground rod. That is from the neutral bar to the ground rod. The panels are on the outside of the buildings. I've checked from neutral bar to ground rod and from the receptacle ground to wet concrete in the building. About 34 volts with pole lights on.


 
I agree wit the post above yours. High resistance grounded conductor connection somewhere upstream.

Is the service underground? Could be a bad crimp at the weatherhead


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## hardworkingstiff

I'm dense, you are reading from the receptacle ground to where to read 32 volts?


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## Cirus

wendon said:


> It sounds to me like you've got a short to ground on one of your feeders. I would shut off each breaker and see when the voltage goes away. Possibly one of the pole lights or the service are shorted to ground. The light could be improperly grounded (or not grounded at all) Could be a host of things. Have you had the POCO check out the primary side? If they have a bad connection or something of the sort, you might be getting return current on the ground rod when you apply the load. Are the services to the pole lights underground or over head?


The poles are wood and fed underground with 3 wire URD. All 3 conductors are insulated. The lights are grounded in a jbox 40' in the air. No,I have'nt contacted the power company.


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## Cirus

hardworkingstiff said:


> I'm dense, you are reading from the receptacle ground to where to read 32 volts?


wet concrete inside the buildings or the ground rod outside the building with the ground wire removed. When I say wet concrete I mean I made it wet to conduct better


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## Cirus

mcclary's electrical said:


> I agree wit the post above yours. High resistance grounded conductor connection somewhere upstream.
> 
> Is the service underground? Could be a bad crimp at the weatherhead


The service is underground. Padmount transformer to the meter base. About a 10' feed from one to the other.


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## wendon

Cirus said:


> The poles are wood and fed underground with 3 wire URD. All 3 conductors are insulated. The lights are grounded in a jbox 40' in the air. No,I have'nt contacted the power company.


Interesting, I would try turning off the lights one at a time while monitoring the voltage between your ground rod and your neutral. Has it been a problem for a while or is it something new? Usually, when a URD gets a break in the insulation, it doesn't take long for the conductor to burn apart. I suppose those lights aren't used every day for long periods. If the voltage level slowly drops as you remove the load from the panel, I would suspect a connection on the POCO side. Just my opinion. As has been stated you need a bonding jumper between the grounding conductor and the grounded conductor but if you have a short underground you'll get return current on the ground rod.


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## Big John

I agree with shutting off breakers one at a time, because it will show you one of two things: If you get gradual drop-off in ground voltage (and you could also check current) as the load decreases, then it's like _wendon _said, it's probably a high resistance neutral at our upstream of the MDP.

But, if you're reading a fault in an underground line on one of your light poles that's using the earth as a parallel path, then opening the breaker for that pole will immediately clear this problem.

At least this way you know where to start looking.

-John


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## Cirus

wendon said:


> Interesting, I would try turning off the lights one at a time while monitoring the voltage between your ground rod and your neutral. Has it been a problem for a while or is it something new? Usually, when a URD gets a break in the insulation, it doesn't take long for the conductor to burn apart. I suppose those lights aren't used every day for long periods. If the voltage level slowly drops as you remove the load from the panel, I would suspect a connection on the POCO side. Just my opinion. As has been stated you need a bonding jumper between the grounding conductor and the grounded conductor but if you have a short underground you'll get return current on the ground rod.


It didn't start until the lights were installed and turned on. The condition is in both buildings but isn't noticed in the bathrooms since no one has contact with electricity except to turn on a light switch. The lights are turned on for about 4 hours twice a month. All three panels are bonded from neutral bar to can with ground rod at all three locations. I've thought about the short underground scenerio. I've had lots of experience with burnt urd and splicing it


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## hardworkingstiff

It's kind of odd that the voltage from ground wire to ground increases with the use of lights that are wired 240-volts.

I wish we knew what the H to ground rod voltage was when the ground wire to ground is 34 volts (also N to ground rod)


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## wendon

Cirus said:


> It didn't start until the lights were installed and turned on. The condition is in both buildings but isn't noticed in the bathrooms since no one has contact with electricity except to turn on a light switch. The lights are turned on for about 4 hours twice a month. All three panels are bonded from neutral bar to can with ground rod at all three locations. I've thought about the short underground scenerio. I've had lots of experience with burnt urd and splicing it


If the bathroom floor is concrete you could probably find voltage from it to the ground on a receptacle. If you want to check the reading from a bare concrete floor, you can put some table salt on a small area, dampen it, and then put a copper plate etc. on it to get a contact reading. I've seen as high as 40 volts coming off a concrete floor when there's a short to ground.


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## Cirus

Big John said:


> I agree with shutting off breakers one at a time, because it will show you one of two things: If you get gradual drop-off in ground voltage (and you could also check current) as the load decreases, then it's like _wendon _said, it's probably a high resistance neutral at our upstream of the MDP.
> 
> But, if you're reading a fault in an underground line on one of your light poles that's using the earth as a parallel path, then opening the breaker for that pole will immediately clear this problem.
> 
> At least this way you know where to start looking.
> 
> -John


As soon as we get a chance thats what I'll do. The MDP and the buildings are around 500' or so from each other so it will take 2 men and radios to get it done.


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## Aussielec

Big John said:


> I agree with shutting off breakers one at a time, because it will show you one of two things: If you get gradual drop-off in ground voltage (and you could also check current) as the load decreases, then it's like _wendon _said, it's probably a high resistance neutral at our upstream of the MDP.
> 
> But, if you're reading a fault in an underground line on one of your light poles that's using the earth as a parallel path, then opening the breaker for that pole will immediately clear this problem.
> 
> At least this way you know where to start looking.
> 
> -John


Yep totally agree, best way to do it IMO. It really does sound like a High or open ciruit main neutral somewhere. His return path would be not only back through the main neutral but also a parrellel path back through the ground.

My guess is that without the sport's light's on there isn't much load so the current returning via this parrellel path is minimal, hence the voltage drop is small aswell. But as you increase the load the current increases, hence voltage drop become's larger and voltage difference start forming throughout the earthing system.


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## wendon

hardworkingstiff said:


> It's kind of odd that the voltage from ground wire to ground increases with the use of lights that are wired 240-volts.
> 
> I wish we knew what the H to ground rod voltage was when the ground wire to ground is 34 volts (also N to ground rod)


If there's a high resistance connection on the primary side, it will send return current on the ground because the primary neutral and the secondary are bonded. As you increase the load on the transformer, the return voltage will go up.


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## Big John

hardworkingstiff said:


> It's kind of odd that the voltage from ground wire to ground increases with the use of lights that are wired 240-volts...


 That's why I'm leaning towards the pole-feeder-fault theory. Without a lot of 120V loads, I have trouble seeing how a balanced 240V lighting load would play into a bad neutral.

-John


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## Cirus

wendon said:


> If the bathroom floor is concrete you could probably find voltage from it to the ground on a receptacle. If you want to check the reading from a bare concrete floor, you can put some table salt on a small area, dampen it, and then put a copper plate etc. on it to get a contact reading. I've seen as high as 40 volts coming off a concrete floor when there's a short to ground.


I've never heard of that method, thanks. I was talking to another electrician friend the other day he suggested a short in the ground somewhere. He called it " leakage "


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## Cirus

A little more info just for kicks. The poles have anywhere from 3 to 7 sport lighters on them. The fixture whips all come together at the top of the poles in a metal raintght Jbox. The splice are made with what we call " polaris " connectors. The lights are grounded and for kicks I bonded the Jbox to ground also. The poles are wood but I was paranoid I guess. I envisioned a short in the Jbox on a rainy day and someone touching the pole at the bottom.:laughing: Since the distances are so great to all of the poles I have a 2 circuit raintight enclosure at the bottom of each pole. Each pole is fused in the enclosure according to the amount of lights on them. All poles are fed with 2 # 8 THHN and 1 # 10 THHN for ground from the enclosure at the bottom. Since the distances are so great to each pole all the URD was oversized due to voltage drop. I know I have one run to a pole that is almost 600'. Every pole has a Jbox at the bottom were the URD feeds in and is tapped down with Polaris connectors so I could feed the 2 circuit panels at the bottom. Its an odd site to see 4/0 Al tapped down to a # 8 copper.:laughing: All this info probably isn't relevent but I thought I would throw it in just so you could picture whats going on.


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## sparkie2010

Cirus said:


> The mdp and subpanels cans are both bonded to the neutral


When you bond your panel then sub-panels you will start to get voltage on your ground. You need to just have one point where your bonding is made. Thats normally at the MDP.


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## Cirus

sparkie2010 said:


> When you bond your panel then sub-panels you will start to get voltage on your ground. You need to just have one point where your bonding is made. Thats normally at the MDP.


There is 3 wire URD going to the subpanels. They have to be bonded in order to have a ground to clear a short. Read the previous posts. There is only voltage when the 240 volt pole lights are turned on. There is no more load on the neutral when the lights are on than when there off.


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## sparkie2010

Cirus said:


> There is 3 wire URD going to the subpanels. They have to be bonded in order to have a ground to clear a short. Read the previous posts. There is only voltage when the 240 volt pole lights are turned on. There is no more load on the neutral when the lights are on than when there off.


Three wires. So you have two hot and a grounded conductor from the MDP to a sub-panel and no ground wire. 

Now your post stats that only when you turn the lights on (120v circuit) that's when you get 34v on your ground.

That 34v is your unbalance load returning upstream. 

What is URD? Also what type of conduit are you using. PVC, emt, Grc.?

Last if you want to test this theory, add a bunch of 120v loads to that circuit and then measure from ground to slab


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## sparkie2010

Ok URD Cable.

Yeah your getting the unbalance on your ground on the 120v circuits. For a 240v load system the URD works fine.


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## Cirus

sparkie2010 said:


> Ok URD Cable.
> 
> Yeah your getting the unbalance on your ground on the 120v circuits. For a 240v load system the URD works fine.


There are no 120 volt circuits at the MDP. There are 16 double pole breakers feeding 16 light poles that are tapped 240 volt. There is a double pole breaker feeding the concession and a double pole feeding the restrooms. You can turn off the mains in the subpanels and kill all power in the two buildings and when you turn on the 240 volt pole lights at the MDP you get about 34 volt from the kitchen equipment surface to the wet concrete floor. I haven't had time to check but right now I'm not sure if the voltage is coming off the equipment or from the concrete floor. Gonna have to do some checking.


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## hardworkingstiff

Cirus said:


> I haven't had time to check but right now I'm not sure if the voltage is coming off the equipment or from the concrete floor. Gonna have to do some checking.


What methodology would one use to do this check? I'm serious about this question, I really would like to know/understand.

Thanks,


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## kbsparky

Sounds like one of them poles has a leaking URD feeder cable. Leaking to ground, and that is backfeeding thru the slab into the concession buildings.

Turn off those lights one circuit at a time and report on whether the 34 volt reading gradually lessen, or all at once with a specific breaker.


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## Cirus

hardworkingstiff said:


> What methodology would one use to do this check? I'm serious about this question, I really would like to know/understand.
> 
> Thanks,


I've been pondering this myself. Gonna try to check it out Friday evening after work.


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## Cirus

kbsparky said:


> Sounds like one of them poles has a leaking URD feeder cable. Leaking to ground, and that is backfeeding thru the slab into the concession buildings.
> 
> Turn off those lights one circuit at a time and report on whether the 34 volt reading gradually lessen, or all at once with a specific breaker.


Thats what I'm thinking also. I'll report back this weekend.


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## hardworkingstiff

Cirus said:


> I've been pondering this myself. Gonna try to check it out Friday evening after work.


Info check please.

Voltage is present between concrete and premise wiring ground conductor (at an outlet) when the main disconnect grounded conductor is grounded to ground rods, but if the ground rod conductor is separated from the grounded conductor (no reground of the neutral at the main) the voltage is no longer present (with the lights on in both scenarios)?


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## Cirus

Thats what I'm gonna check on. One other thing that might come into play. There is a propane tank about 60' from the concession. From the tank there is a copper line feeding the concession where it connects to rigid gas pipe, goes into the building, down a wall where it T's off to a gas grill, goes down through the wall further where it ties into the gas central heating unit. The heating unit of course plugs into a 120 volt outlet that runs the blower. So, the 34 volts could also be coming in on the gas line and feedng back onto the ground of the 120 volt outlet. Just a guess.


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## Cirus

hardworkingstiff said:


> Info check please.
> 
> Voltage is present between concrete and premise wiring ground conductor (at an outlet) when the main disconnect grounded conductor is grounded to ground rods, but if the ground rod conductor is separated from the grounded conductor (no reground of the neutral at the main) the voltage is no longer present (with the lights on in both scenarios)?


Besides it possibly coming back on the ground rod at the subpanels, could it also be feeding back at the ground rod at the MDP? Maybe I should disconnect all 3 rods if it is a leakage on one of the hots going to a light pole. We'll see.


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## wendon

Cirus said:


> Besides it possibly coming back on the ground rod at the subpanels, could it also be feeding back at the ground rod at the MDP? Maybe I should disconnect all 3 rods if it is a leakage on one of the hots going to a light pole. We'll see.


If I was a betting man, I'd put my money on the bad UD cable. Is the UD in conduit or is it direct buried? If it was a short on one of the lights it would probably trip the breaker. I had a customer call me one time and said the new equipment we installed was giving him shocks. Went out and checked and found about 30 volts between the floor and the equipment. The funny thing was it would come and go. Finally figured out it was coming from the well. Went out to the well head and found the problem. The underground water line had went bad so they brought a temporary line up out of the well head and teed off to go to two different buildings. He had mowed his lawn that day and bumped into the water line. The line pushed against the side of the well casing and pinched the wire going to the submersible pump. The well casing wasn't grounded so it fed the current into the ground.


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## Cirus

wendon said:


> If I was a betting man, I'd put my money on the bad UD cable. Is the UD in conduit or is it direct buried? If it was a short on one of the lights it would probably trip the breaker. I had a customer call me one time and said the new equipment we installed was giving him shocks. Went out and checked and found about 30 volts between the floor and the equipment. The funny thing was it would come and go. Finally figured out it was coming from the well. Went out to the well head and found the problem. The underground water line had went bad so they brought a temporary line up out of the well head and teed off to go to two different buildings. He had mowed his lawn that day and bumped into the water line. The line pushed against the side of the well casing and pinched the wire going to the submersible pump. The well casing wasn't grounded so it fed the current into the ground.


The URD is direct buried. How far was the well from the floor of the building your talking about? I've never run into this problem before and just wondering how far voltage can run in a situation like this?


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## hardworkingstiff

hardworkingstiff said:


> Info check please.
> 
> Voltage is present between concrete and premise wiring ground conductor (at an outlet) when the main disconnect grounded conductor is grounded to ground rods, but if the ground rod conductor is separated from the grounded conductor (no reground of the neutral at the main) the voltage is no longer present (with the lights on in both scenarios)?





Cirus said:


> Besides it possibly coming back on the ground rod at the subpanels, could it also be feeding back at the ground rod at the MDP? Maybe I should disconnect all 3 rods if it is a leakage on one of the hots going to a light pole. We'll see.


Cirus, your answer did not match my question. 

If you get some time, could you tell us (me) again about what happened when you altered the re grounding of the neutral?

How many times is that neutral grounded and at which locations?

A sketch of panels and grounding might help.

Thanks and I hope you share your findings.


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## Cirus

hardworkingstiff said:


> Cirus, your answer did not match my question.
> 
> If you get some time, could you tell us (me) again about what happened when you altered the re grounding of the neutral?
> 
> How many times is that neutral grounded and at which locations?
> 
> A sketch of panels and grounding might help.
> 
> Thanks and I hope you share your findings.


The MDP is bonded and grounded and so are the two subpanels. A ground rod at all panels. When I check it out I'll let you know my findings. Oh yea, the voltage is still present when the ground rod is disconnected with the lights on. No lights, no voltage.


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## hardworkingstiff

Cirus said:


> The MDP is bonded and grounded and so are the two subpanels. A ground rod at all panels. When I check it out I'll let you know my findings. Oh yea, the voltage is still present when the ground rod is disconnected with the lights on. No lights, no voltage.


Based on this I'm with whoever said it's a wire leaking voltage. My I suggest you put an ampmeter on the conductors leaving the panel and look for an unbalanced load on one of the circuits?


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## sparkie2010

Are you able to turn on one light pole at a time?

Just wondering if you can isolate the bad end or is it just the feed thats bad?

Also if you can give the distance from the pole to the pad the your getting the 30v.
Just would like to know if we can calculate the amount of difference of potential that you have from pole to pad. 

Thanks


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## Cirus

Alright, did a little checking at the concession panel and here is what I found. I disconnected the ground wire from the rod. There is also concrete about 2' away from the ground rod and I checked from both and the findings were the same. I turned the main off for the concession at the MDP. No voltage to the concession. I had my son go to the MDP and slowly turn on the double pole breakers to the poles one at a time while I was at the concession panel which is outside, and I checked from neutral to ground rod and wet concrete. As he turned the lights on I saw an increase of 1.5-2 volts per pole. The poles have anywhere from 3 to 7 lights on them. When all 16 poles were on I had about 34 volts from rod/concrete to neutral. No problems to the poles correct? 

I then turned the main to the concession back on at the MDP. This is where I found something interesting. All 16 poles are on. This is what I found at the concession panel. Minimal load at the concession, maybe a couple of refrigerators cycling on and off. No other loads. Neutral to ground rod=34 volts. Phase to phase=230-231 volts. Phase to neutral=115. Phase to neutral=115. Phase to rod=149. Phase to rod=81. A 34 volt difference from phase to rod compared to phase to neutral. The same readings from wet concrete also. That tells me I'm getting 34 volts from the ground and not the neutral. No backfeed which I couldn't see with a balanced load. Should I call the local power company? I say yes.


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## wendon

Cirus said:


> Alright, did a little checking at the concession panel and here is what I found. I disconnected the ground wire from the rod. There is also concrete about 2' away from the ground rod and I checked from both and the findings were the same. I turned the main off for the concession at the MDP. No voltage to the concession. I had my son go to the MDP and slowly turn on the double pole breakers to the poles one at a time while I was at the concession panel which is outside, and I checked from neutral to ground rod and wet concrete. As he turned the lights on I saw an increase of 1.5-2 volts per pole. The poles have anywhere from 3 to 7 lights on them. When all 16 poles were on I had about 34 volts from rod/concrete to neutral. No problems to the poles correct?
> 
> I then turned the main to the concession back on at the MDP. This is where I found something interesting. All 16 poles are on. This is what I found at the concession panel. Minimal load at the concession, maybe a couple of refrigerators cycling on and off. No other loads. Neutral to ground rod=34 volts. Phase to phase=230-231 volts. Phase to neutral=115. Phase to neutral=115. Phase to rod=149. Phase to rod=81. A 34 volt difference from phase to rod compared to phase to neutral. The same readings from wet concrete also. That tells me I'm getting 34 volts from the ground and not the neutral. No backfeed which I couldn't see with a balanced load. Should I call the local power company? I say yes.


I would suspect something on the conductors between the POCO's xfmr secondary and your main disco. If it was returning from the primary, I don't think you would see an imbalance like you're seeing. If you had a way of making sure there was equal current draw on both legs of your main disconnect and the voltage between the ground and the neutral bar was low, it would probably confirm it. How far is the transformer from the MDP? If you had a way to clamp an amp meter around all the phase conductors where they come off the pole, you might be able to see if you have a leak to ground.


----------



## hardworkingstiff

Would that 34-volts your reading flash if you connected across it with a conductor? In other words, how much kick is behind that 34-volts.

What is strange is the was earth ground is being raised to the B-phase, just a little at a time with the light circuits being turned on.


----------



## Cirus

wendon said:


> I would suspect something on the conductors between the POCO's xfmr secondary and your main disco. If it was returning from the primary, I don't think you would see an imbalance like you're seeing. If you had a way of making sure there was equal current draw on both legs of your main disconnect and the voltage between the ground and the neutral bar was low, it would probably confirm it. How far is the transformer from the MDP? If you had a way to clamp an amp meter around all the phase conductors where they come off the pole, you might be able to see if you have a leak to ground.


The transformer is about 10' from the meter base. There is a pole about 500' away. From there they brought primary to the center of the track and hit the transformer, then the meter base. I ran the conduit for the secondary from the transformer to the meter base. Two 4" pvc. Don't know what they fed to the meter base with.


----------



## Cirus

wendon said:


> If you had a way to clamp an amp meter around all the phase conductors where they come off the pole, you might be able to see if you have a leak to ground.


Yea, my meter is not big enough to clamp around all the conductors on my side. May have to get the poco to open up the meter base. I assume they paralleled the secondary but I wasn't there when they did the work. I've got 4 conductors per phase on my side.


----------



## wendon

hardworkingstiff said:


> Would that 34-volts your reading flash if you connected across it with a conductor? In other words, how much kick is behind that 34-volts.
> 
> What is strange is the was earth ground is being raised to the B-phase, just a little at a time with the light circuits being turned on.


Agreed! I think we have gremlins at work! Maybe we better bring out the tin foil hats!!arty:arty:


----------



## wendon

Cirus said:


> Yea, my meter is not big enough to clamp around all the conductors on my side. May have to get the poco to open up the meter base. I assume they paralleled the secondary but I wasn't there when they did the work. I've got 4 conductors per phase on my side.



Maybe a guy could hook a number of these in series?


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## noarcflash

Is the netural downsized at all ... anywhere ?? maybe it's a simple voltage drop across the netural from the excesive distance.


----------



## hardworkingstiff

noarcflash said:


> Is the netural downsized at all ... anywhere ?? maybe it's a simple voltage drop across the netural from the excesive distance.


But, there's not neutral load from the lights (at least that's what I understood the OP to say).


----------



## Cirus

hardworkingstiff said:


> But, there's not neutral load from the lights (at least that's what I understood the OP to say).


All the lights are tapped 240 volt. There are 16 poles and each pole has its own 50 amp service and breaker. The maximum number of lights on a pole are 7. Thats comes to around 31.5 amps. There are anywhere from 3 to 7 lights per pole. There is a raintight panel and breaker and the bottom of each pole. The breaker at the bottom of the pole is sized according to the amount of lights on that pole. When I get to my supply house in the morning, I'm gonna see if they can get me an amp meter or some accessory that will adapt to mine to go around that many wires so I can get a reading. The main in the MDP has quadraplex legs and they are all fed. So I've got 4 wires I need to clamp around.


----------



## Cirus

noarcflash said:


> Is the netural downsized at all ... anywhere ?? maybe it's a simple voltage drop across the netural from the excessive distance.


The only neutral load is the services to the concession and restroom. There is a 350 mcm to the restrooms and a 500 mcm to the concession. As you can imagine there is no load in the restrooms , just a few lights. The concession is vertually all gas. A few counter top appliances and a few lights. Gas central heat and gas grill. Just 240 volt a/c unit outside. Very little load at the concession. I get the 34 volts even when the mains to the subpanels are off.


----------



## hardworkingstiff

Cirus said:


> I get the 34 volts even when the mains to the subpanels are off.


And the lights are on, right? Lights off, no voltage.


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## Cirus

hardworkingstiff said:


> And the lights are on, right? Lights off, no voltage.


Correct!


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## noarcflash

The neighbor has a bad neutral.
My house, there is always ground current, even with my main service off.


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## wwilson174

hardworkingstiff said:


> But, there's not neutral load from the lights (at least that's what I understood the OP to say).


Perhaps some lights are miswired , has the current on the neutral been measured? BillW


----------



## Cirus

noarcflash said:


> The neighbor has a bad neutral.
> My house, there is always ground current, even with my main service off.


Not in the this situation. There is no neighbor. Just wondering. We did the trenching and laid the pvc for the primary to the transformer, about 500'. On each end of the pvc the poco had us turn up with galvanized rigid 90' sweeps. They said that with that long a run the wire might burn through the 90's when they pulled in the primary. I wonder if the primary could be bleeding through to the rigid sweeps? Just a thought.


----------



## Cirus

wwilson174 said:


> Perhaps some lights are miswired , has the current on the neutral been measured? BillW


I don't think so. I tapped all of them myself. Besides, how long would a ballist last fed with 240 but tapped with 120/208/277. The've been burning for quite some time with no problems. Also the voltage increased slowly as I turned the lights on. You could tell when each pole was turned on. 1.5-2.0 volts per pole.


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## noarcflash

there's your problem. you have a multitap fixture. one of the leads NOT BEING USED, is not capped off properly, and touching ground.


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## hardworkingstiff

noarcflash said:


> there's your problem. you have a multitap fixture. one of the leads NOT BEING USED, is not capped off properly, and touching ground.


On each light pole? I guess it could be, same problem on each pole?


----------



## Cirus

noarcflash said:


> there's your problem. you have a multitap fixture. one of the leads NOT BEING USED, is not capped off properly, and touching ground.


Nope. They were all tapped 277 from the factory. I retapped to 240 and capped off the 277 lead. All the other leads were capped off. Besides all the fixtures are grounded. It would throw the breaker at the bottom of the pole. Like I said earlier, the voltage increases with every pole you turn on. Its not that.


----------



## Big John

You describe this test where you measure the 34 volts to earth with all the ground rods disconnected, correct?

But with the ground rods connected under normal conditions, people are getting shocked between equipment and earth? What is the voltage under those conditions?

I am started to be very tempted to say that the POCO transformer secondary is not grounded, and that you are grounding that point, but I'm not 100% sure how that explains the voltages.

-John


----------



## Cirus

Big John said:


> You describe this test where you measure the 34 volts to earth with all the ground rods disconnected, correct?
> 
> But with the ground rods connected under normal conditions, people are getting shocked between equipment and earth? What is the voltage under those conditions?
> 
> I am started to be very tempted to say that the POCO transformer secondary is not grounded, and that you are grounding that point, but I'm not 100% sure how that explains the voltages.
> 
> -John


Correct. Voltage is the same with the rods connected. I can pick up the voltage off wet concrete as I've said earlier. If the concrete is dry is around 8-10 volts. The conditions have to be right. The concrete has to be wet or you have to be wet to get the full effect. I've been in the concession with the pole lights on and don't get a tingle unless I wet my hand or reach from equipment to floor or kneel down and touch equipment.


----------



## Big John

Did you ever grab any current measurements? You have 3 ground points in this system: One at the MDP, one each at the two concession subs, correct?

-John


----------



## Cirus

Big John said:


> Did you ever grab any current measurements? You have 3 ground points in this system: One at the MDP, one each at the two concession subs, correct?
> 
> -John


Correct. I posted the measurements earlier from the concession. Gonna try to get an amp meter large enough to fit around the 4 conductors I have paralleled to each phase.


----------



## Big John

So, when you've been disconnecting the ground rod to get a measurement, you're not actually ungrounding the whole system, you're just removing 1 of the 3 ground points?

I was thinking current measurements for the electrode conductors. I didn't see those?

-John


----------



## Aussielec

Cirus said:


> Nope. They were all tapped 277 from the factory. I retapped to 240 and capped off the 277 lead. All the other leads were capped off. Besides all the fixtures are grounded. It would throw the breaker at the bottom of the pole. Like I said earlier, the voltage increases with every pole you turn on. Its not that.


These are outside lights right? If so, it's not unusual to get a bit of leakage to earth through the ballast's after some time. This would explain why as you turn the lights on the voltage between the frame and the wet cement increases. It sounds like cumulative affect. Just curious have you meggered the cables that run to the lights?

My guess is that you're getting a parrellel path established back to the lighting SB via the ground and ground rod. This inturn will create step potentials between the light post and earth rod and then end up manifesting themselves into touch potential as far the earthed equipment goes. Just a thought anyway.


----------



## Cirus

Aussielec said:


> These are outside lights right? If so, it's not unusual to get a bit of leakage to earth through the ballast's after some time. This would explain why as you turn the lights on the voltage between the frame and the wet cement increases. It sounds like cumulative affect. Just curious have you meggered the cables that run to the lights?
> 
> My guess is that you're getting a parrellel path established back to the lighting SB via the ground and ground rod. This inturn will create step potentials between the light post and earth rod and then end up manifesting themselves into touch potential as far the earthed equipment goes. Just a thought anyway.


The light poles are wood. How would that be possible? I understand the leakage but how is it gonna get back to earth with a wood pole?


----------



## wendon

I would recommend you contact the POCO and have them see if it's something on their end. If they're anything like the ones in my area, they'll be glad to help you troubleshoot it. The other choice is to meg all the wires. If the voltage was there when everything was shut off it could be from a neighboring source but it sounds like it something on site. I would suspect something with the transformer, the primary, or the secondary connections or conductors. If I lived in your area, I'd help you troubleshoot it for nothing!!


----------



## Cirus

wendon said:


> If I lived in your area, I'd help you troubleshoot it for nothing!!


Would a case of beer cover it?:laughing:


----------



## Aussielec

Cirus said:


> The light poles are wood. How would that be possible? I understand the leakage but how is it gonna get back to earth with a wood pole?


Yeah I assumed they were metal....


----------



## kbsparky

Cirus said:


> The light poles are wood. How would that be possible? I understand the leakage but how is it gonna get back to earth with a wood pole?


If each pole was supplemented with a ground rod, the scenario outlined is extremely possible. What condition is the EGC? Has the continuity and size of it been verified?


----------



## Spark Master

I say electrons will flow through wood to get back to earth. Electrons flow through dirt and earth, why not wood ???


----------



## hardworkingstiff

Spark Master said:


> I say electrons will flow through wood to get back to earth. Electrons flow through dirt and earth, why not wood ???


To add support to your argument, if they are treated poles, the wood treatment may very well be a conductive material.


----------



## Cirus

Went ahead and called the poco. I also ordered a new Fluke with a I-Flex lead to check my parallel conductors at the mdp. I had a few minutes yesterday and took a couple of readings at the mdp. From ground wire to ground rod or earth I got 34 volts with the lights on just like everywhere else. Also, should you get a reading from the padmount transformer frame to the earth? I did. 31 volts.


----------



## Cirus

I also noticed recently that I still get a little voltage from ground wire to rod/earth even when lights are off. About 1.5 volts when concession and bathroom are running, just very light load. When all load is gone from these two buildings it reads 0. When any load is applied to the system I get voltage readings. I wonder if removing the ground rods at the subpanels would have any effect? I don't see how.


----------



## hardworkingstiff

Cirus said:


> Went ahead and called the poco. I also ordered a new Fluke with a I-Flex lead to check my parallel conductors at the mdp. I had a few minutes yesterday and took a couple of readings at the mdp. From ground wire to ground rod or earth I got 34 volts with the lights on just like everywhere else. Also, should you get a reading from the padmount transformer frame to the earth? I did. 31 volts.


You took your readings with the ground rods connected? How did you take your readings (what did you put in the earth, how far into the earth)? Did you take measures to alleviate ghost voltages (using a low impedance meter or putting a small load paralleling the test points)?


----------



## Cirus

I disconnected the ground wire from the ground rod at the mdp. Thats how i got my reading. I also got that reading from the ground wire to the earth by just sticking meter leads from ground wire to earth. The other 2 rods at the subpanels were still intact.


----------



## hardworkingstiff

Cirus said:


> I disconnected the ground wire from the ground rod at the mdp. Thats how i got my reading. I also got that reading from the ground wire to the earth by just sticking meter leads from ground wire to earth. The other 2 rods at the subpanels were still intact.


How old is this electrical system? How old are the ground rods?


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## Cirus

New rods. Sandy soil. Lightng is a few months old. When I first checked voltage before the light were installed I had 125/250 no load. Now 121/242 with no load. Vertually no load unless lights are on. Why the drop I wonder?


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## Big John

I wouldn't worry about the 1.5 volts you're seeing at your concession stands. I think that's to be expected with neutral loads on a 3 wire system.

I wouldn't worry about the slight change in voltage you've seen from 250 to 242. Utilities adjust primary voltage all the time. If it keeps dropping, obviously that's a different story.

I'm still leaning towards a POCO problem for the 34V. But current measurements might make this a lot clearer.

-John


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## Cirus

As soon as I get the Fluke we'll see. I did check a few of the feeds to the poles with meter I have. Kinda hard to ge the clamp in there but the ones I did check were balanced with 0 on the ground wire.


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## hardworkingstiff

hardworkingstiff said:


> Did you take measures to alleviate ghost voltages (using a low impedance meter or putting a small load paralleling the test points)?


You didn't answer this question.


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## 8V71

Cirus said:


> Also, should you get a reading from the padmount transformer frame to the earth? I did. 31 volts.


^^^^


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## Cirus

hardworkingstiff said:


> You didn't answer this question.


The meter I have now has no low impedance setting. The Fluke I ordered does I believe.


----------



## A Little Short

cirus said:


> ive got an h frame with a single phase 240 volt 1200 amp service and mdp in the middle of a race track. It has 16 double pole 50 amp breakers feeding 16 poles with around a hundred 1000 watt sports lighters. It has a 50 amp 240 volt service feeding restrooms about 500 feet away and 150 amp 240 volt service feeding a concession stand also about 500 feet away. The sports lighters are tapped for 240 volt. Everything is fed underground using 3 wire urd.
> 
> Voltage is good and everything works like a charm except when the pole lights are turned on i'm getting around 34 volts on the ground of the 120 volt receptacles. Of course on some of the appliances you get a tingle if you touch the appliance and the concrete with a wet hand. Both buildings have there own subpanels with ground rods at both. Neutrals and grounds are on seperate bars but the bonding jumpers are installled.
> 
> 
> When jumpers are removed the reading goes back to zero. When the lights are turned off the voltage from the receptacle ground to the wet concrete goes back to zero. If the concretes dry it might read 7 or 8 volts. Turning off the main in the subpanels has no effect. I assume i'm getting a backfeed on the neutral but why? The only 120 volt loads are at the two buildings since the pole lights are 240 volt so neutral load is lite. I've never run into this before and i've dealt with 3 wire 240 volt subfeeds many times with same circumstances. Any ideas?




update please!!!!


----------



## Cirus

Update. Talked to the engineer from the poco that handled the job several weeks ago and she said she would tell the head lineman and get back with me. Didn't hear anything for a couple of weeks so I called her back. She turned it over to some troubleshooter out of the DFW office. He called me, asked a bunch of questions and said that look into it. The next day which was Friday, about 6 poco trucks showed up at the track. I wasn't there but the owner said they took several readings with the lights on and said there was definitely something wrong. They said they would be back and check some more but would turn in the readings to the guy out of DFW. So thats where we're at. I talked to a friend who is also an electrician and he said he had dealt with the same problem on a job. He said they never did find the problem and the poco couldn't either. He said they drove sectional rods until it went away. The guy from DFW did ask me if it was sandy soil and I said very sandy. I ask the owwner how deep the sand was and he said about 16 feet. I took some readings with my new Fluke with the I-Flex lead and everything was balanced. 375 amps on each phase and 0 on the neutral as was expected. It rained about 3 inches the other day and I took some readings right after and I got about 43 volts this time instead of 34 volts. You can get a tingle from the fence if you touch one of the panels at the bottom of the poles at the same time. I had a guy tell me the other day that he had got shocked at the fence and I told him he was crazy since the fence and the ground was at the same potential. I asked him if he had maybe touched one of the panels at the bottom of one of the poles ant the same time and he said he thinks he did. I said that makes sense then. Anyway, thats where we're at.


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## Big John

Did you ever take current readings on your grounding-electrode conductor? 

-John


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## Cirus

yep 0


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## hardworkingstiff

Cirus said:


> Update.....Anyway, thats where we're at.


Thank you so much for the update.

Curious, did you ever look inside one of the fixtures to inspect the wiring? Specifically, is the bonding wire properly connected?


----------



## Cirus

Yep. My helper and myself did all the connections to the lights.


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## 8V71

Big John said:


> Did you ever take current readings on your grounding-electrode conductor?
> 
> -John





Cirus said:


> yep 0


I would think there must be some current there. Did you look at it on the milliamp scale?


----------



## Cirus

There shouldn't be on 240v loads.


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## 8V71

Cirus said:


> There shouldn't be on 240v loads.


You're right there shouldn't be. Shouldn't be on 120 volt loads either. You are feeling a shock and measuring voltage so I would think there must be some current there if it's shocking people.


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## 8V71

Since you are measuring voltage to earth at the padmount my thoughts are they have a flaky neutral connection somewhere between the substation and your location.

They might end up doing the sectional rod thing like in your friends situation rather than trying to find it.


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## Cirus

They said they were gonna check the overhead lines leading into the property which is a long way. If they can't find anything I'll have to do the sectionals myself if they won't. The guy from the head office said sometimes they just can't find it. Not very comforting.


----------



## hardworkingstiff

Cirus said:


> They said they were gonna check the overhead lines leading into the property which is a long way. If they can't find anything I'll have to do the sectionals myself if they won't. The guy from the head office said sometimes they just can't find it. Not very comforting.


Sounds like the PoCo has taken ownership of the problem (or at least considering they have a deteriorating connection). That's a good sign.


----------



## 8V71

Something else that may be occuring where no one is at fault per say. Normal voltage drop on the primary but different earth ground resistance along the way. I'm surprised that your voltage reading went up instead of down when it rained though.


----------



## Big John

8V71 said:


> ...I'm surprised that your voltage reading went up instead on down when it rained though.


 The only thing I can think to explain that: If this is a primary-neutral problem causing excessive earth return current, then when it rains the earth resistance between POCO neutral grounds decreases and the current flow increases, which would increase the voltage drop.

-John


----------



## don_resqcapt19

Big John said:


> The only thing I can think to explain that: If this is a primary-neutral problem causing excessive earth return current, then when it rains the earth resistance between POCO neutral grounds decreases and the current flow increases, which would increase the voltage drop.
> 
> -John


The total primary current does not change because you have other paths in parallel with the actual conductor. Lowering the resistance of any of the parallel paths cannot cause an increase in the voltage drop. The lower the total resistance of all of the paths the lower the voltage drop and since these paths are in parallel they have have the same voltage drop.


----------



## Aussielec

don_resqcapt19 said:


> The lower the total resistance of all of the paths the lower the voltage drop and since these paths are in parallel they have have the same voltage drop.


Not really, I would agree with the first part, but parallel paths don't have the same voltage drop unless they have a reference to the same voltage on the other end.


----------



## don_resqcapt19

Aussielec said:


> ..., but parallel paths don't have the same voltage drop unless they have a reference to the same voltage on the other end.


 If they are not connected to the same point at both ends, they are not connected in parallel.


----------



## Big John

Don may be right on this one. If the voltage is between two rods then the drop doesn't change just because the conductivity changes. When I wrote that I had some half-baked idea about multiple paths from multiple rods and different resistances between those points, and I'm not sure if that actually would make a difference or not.

I'm just at a loss to explain the voltage increase with the wet ground, when that is exactly the opposite of what I would've guessed would happen.

-John


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## Cirus

I've gotta meet with same engineer in the morning on another job. I'll ask her if they came up with any ideas. Don't know if I mentioned earlier but the owner sand the sand was about 16' . I ordered 3 10' sectional rods this morning. When I get the time I'll drive them at the mdp just for good measure.


----------



## A Little Short

Cirus said:


> I've gotta meet with same engineer in the morning on another job. I'll ask her if they came up with any ideas. Don't know if I mentioned earlier but the owner sand the sand was about 16' . I ordered 3 10' sectional rods this morning. When I get the time I'll drive them at the mdp just for good measure.


Don't drive then until the engineer/POCO finishes their studies. You may never find the actual cause then if the rods make the voltage disappear.
You may actually be just putting a band-aid on the problem also, IMO.


----------



## Cirus

Oh no. I have no intention of driving the rods until the poco is through with there study. If they don't find anything then I'll pound them in.


----------



## don_resqcapt19

Cirus said:


> Oh no. I have no intention of driving the rods until the poco is through with there study. If they don't find anything then I'll pound them in.


A better connection to earth is not the answer to this problem. While it is possible (not likely in my opinion, unless there is no connection to earth on the system now) that the additional rods could make the voltage go away, that would only be masking, not solving the problem.


----------



## Cirus

It may not be the answer but if the poco can't find the problem and its not in my system I'll give it a shot. If it will get rid of the voltage thats better than having stray voltage floating round from now on or waiting for something to blow. Who knows, it may help find the problem.


----------



## 8V71

I know it's a long distance but would running 4-wire to your subs be an option? I think it would be a guaranteed fix and you could test it out before doing the work.


----------



## Cirus

What good would a 4th wire do? I'm picking the voltage up through the soil. I have no imbalance in my subpanels or mdp.


----------



## 8V71

I think most people that have commented on this thread believe you are picking up voltage on your neutral for whatever reason, but not because of (hot) circuit imbalance. Long primary and secondary runs (voltage drop with load), poor soil conditions (lost your electrical ground reference), maybe a not so perfect neutral bonding connection. Everything (neutral/GEC) is tied together all the way back to the primary neutral (which carries **all** of the return loads for the entire complex).

You mentioned a while back that the voltage went away when you removed your bonds in the sub panels. Of course you can't leave them like that because of shock hazard/fault path hence the 4th wire idea.

"I'm picking the voltage up through the soil"..... The voltage you are reading is a difference in potential between your neutral/ground and earth ground. Un-bond your neutral/gnd except at the mdp and this problem may go away.


----------



## Cirus

You can get 34 volts from earth to neutral or to the can of my mdp in the center of the track. The mdp is 5' away from the padmount transformer. You can get 34 volts from earth to anyone of the disconnects at the bottom of the light poles. The poles have a 3 wire feed to them and all lights are on 240. What good would a 4th wire do on a 240 volt loads? All the feeds to the light poles are for 50 amp load and sized for voltage drop. The most load on any pole is 31.5 amps. I understand what your saying about voltage drop and I could see that if my conductors were undersized but I overkilled the hell out of it as far as conductor size. I have a 350 mcm good for 100 amps at that distance going to the restrooms and there is nothing in the restroom but 6 flourescent lights. Also, why would I be picking up close to 34 volts off the frame of the transformer? 

Now, if I were picking up voltage off my neutral would I see an increase in voltage from phase to neutral? Right now when all the pole lights are on at either subpanel I get 81 volts from phase A to earth and 149 volts from phase B to earth. A & B to neutral are 115 volts. 230 across both. The voltage increase is linear. 16 poles with 16 increases in voltage on my meter. I can see the voltage being high when all lights are on with 375 amps on each phase but why the increase the minute I turn on the first pole? The lights are 240 with no neutral load. I can go to any 120 volt outlet in either building and check from the hot side of the plug to wet concrete and get 81 or 149 volts depending on what phase the outlet is on. Neutral side of the plug to wet concrete I get 34 volts. If I have to run a 4th wire thats what I'll do but I really don't think thats it. We'll wait and see what the poco says. I appreciate all you guys responses thats for sure. Keep them coming!


----------



## Shockdoc

I'd bet your neutral connection is bad inside the xformer. How long have you been working on this?


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## Cirus

The transformer was set by the poco in May. Its been doing this since we installed the lights. There was no load until we installed the lights. Just a concession and restrooms.


----------



## Cirus

I talked to the engineer yesterday and she said something about possible bad conductors. Where I don't know. I know that the overhead poles are pretty old and come from the highway about 1/2 a mile through dense jungle. 3 of the poles are new where they tied onto the old line. I don't have much experience with transformers but would a bad neutral connection still cause problems even with all 240 volt loads?


----------



## Shockdoc

Cirus said:


> The transformer was set by the poco in May. Its been doing this since we installed the lights. There was no load until we installed the lights. Just a concession and restrooms.


 So the load is your determiner that a there is a bad neutral connection. you checked MPD, metercan connections and GEC connections? Correct? The next and last stop is the xformer where the neutral is derived. If you are getting voltage between can and pad mount ,problem is in the padmount. Bet if you ran a stretch of #6 between the padmount shell and neutral [email protected] your problems would vanish.


----------



## Cirus

I made all connections myself. Tightened the piss out of everything. I'm getting voltage from transformer frame to earth and mdp can to earth. Now my ground rod is only 8' and the sand is almost 16'.


----------



## Shockdoc

Cirus said:


> I made all connections myself. Tightened the piss out of everything. I'm getting voltage from transformer frame to earth and mdp can to earth. Now my ground rod is only 8' and the sand is almost 16'.


Might have a bad neutral/ground connection on the primary end.


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## hardworkingstiff

Shockdoc said:


> Might have a bad neutral/ground connection on the primary end.


That's what I'm leaning towards too. Transformer is fed with one phase and a neutral (ugh, excuse me, grounded conductor). If the grounded conductor coming into the transformer has a corroded connection somewhere (it could be 1/2 a mile away) causing a high impedance path, the grounding of this conductor at the transformer will cause the grounded conductor load to seek a return path through the earth. Since the load on the primary grounded conductor goes up with a load on the transformer the voltage from anything bonded to the neutral of the secondary since it's grounded along with the primary grounded conductor.

The fact that the earth to phase voltage on the secondary swings to one phase has me puzzled though.

I sure hope someone figures this out (instead of trying to ground it away) and we get to read about it here.


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## Cirus

Shockdoc said:


> Bet if you ran a stretch of #6 between the padmount shell and neutral [email protected] your problems would vanish.


If I get a chance I'll give it a shot.


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## Shockdoc

Cirus said:


> If I get a chance I'll give it a shot.


If it does not make any change your problem is definetly a loss of primary grounded conductor or a bad neutral ground termination inside the xformer.


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## Cirus

I'll have some time in the morning. I'll give it a shot and get back to you tomorrow.


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## Cirus

Also, and I think I mentioned it in an earlier post, that when I check from a copper gas line buried in the ground from a propane tank to the concrete slab of the concession I get the 34 volts. The potential is the same. Thought I'd throw that in there.


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## 8V71

Yeah, I’m starting to write things without thinking about my previous posts which were pointing to a primary neutral (grounded conductor) problem. The point I’m trying to make is that your neutral and ground rods are directly connected, or should be, to the primary neutral, and if it rises so will your system. The POCO primary is just 2 wires, a hot and neutral, so all loads including your 240 volt lights will effect this.

Thinking about this more, if you were to unbond your subs and run a test ground wire back to the mdp you would pick the 34 volts back up again if the ground/neutral at the mdp is at this raised potential and it won’t fix anything. Here is something easy you could try if you haven’t already. Unbond your subs and turn the lights on. Measure for the ~34 volts back at the mdp or padmount. Also, turn the breakers off to the subs as another part of this test just to make sure there are no appliances messing with your results. This is important.

In my previous post I wasn’t suggesting 4-wire to your 240 volt lights, just the subs.


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## 8V71

Cirus said:


> Also, and I think I mentioned it in an earlier post, that when I check from a copper gas line buried in the ground from a propane tank to the concrete slab of the concession I get the 34 volts. The potential is the same. Thought I'd throw that in there.


I remember you writing this and it makes sense...I think? :blink: The copper line is attatched to a stove or whatever which is also bonded to your neutral/grounds so it's essentially the same as measuring from your system ground to earth ground which is the problem because they are at different potentials. The sandy soil that the gas line is buried in is doing very little to bring them to the same potential.


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## Cirus

8V71 said:


> Also, turn the breakers off to the subs as another part of this test just to make sure there are no appliances messing with your results. This is important.


Already tried that at the beginning. I turned off the mains to the subs. No help.


----------



## Cirus

8V71 said:


> Yeah, I’m starting to write things without thinking about my previous posts which were pointing to a primary neutral (grounded conductor) problem. The point I’m trying to make is that your neutral and ground rods are directly connected, or should be, to the primary neutral, and if it rises so will your system. The POCO primary is just 2 wires, a hot and neutral, so all loads including your 240 volt lights will effect this.


I got you, I think. So even though the lights are 240 volt that still throws load on the primary neutral. Right? I keep thinking about the secondary neutral having no load on it. As I said earlier, I have very little experience with transformers. Question. If you have a single phase 120/240 transformer and its fed with hot and neutral primary, if you lose the primary neutral than you get nothing right? The transformer will not produce 240 volt without a primary neutral? Even if all your loads were 240 volt it still would not work without a primary neutral? It takes the primary neutral to produce the 2 phases correct?


----------



## 8V71

Cirus said:


> I got you, I think. So even though the lights are 240 volt that still throws load on the primary neutral. Right? I keep thinking about the secondary neutral having no load on it. As I said earlier, I have very little experience with transformers. Question. If you have a single phase 120/240 transformer and its fed with hot and neutral primary, if you lose the primary neutral than you get nothing right? The transformer will not produce 240 volt without a primary neutral? Even if all your loads were 240 volt it still would not work without a primary neutral? It takes the primary neutral to produce the 2 phases correct?


Correct....dead with open primary neutral. 2 phases is really a split phase. A made up phase 180 degrees out from the incoming phase.


----------



## Cirus

8V71 said:


> Thinking about this more, if you were to unbond your subs and run a test ground wire back to the mdp you would pick the 34 volts back up again if the ground/neutral at the mdp is at this raised potential and it won’t fix anything.
> In my previous post I wasn’t suggesting 4-wire to your 240 volt lights, just the subs.


See, thats what was confusing me in some of the earlier posts. Some suggested 4 wires to the subs. I understand that 3 wire feeds can cause problems in a subpanel if you have a phase imbalance, etc. since all your neutrals and grounds are bonded together in the sub but if the imbalance or raised potential is at the mdp neutral running a 4th wire and isolating the grounds and neutrals at the sub won't solve anything. You'll just be sending the 34 volts to the ground bar in the panel.


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## Cirus

8V71 said:


> Correct....dead with open primary neutral. 2 phases is really a split phase. A made up phase 180 degrees out from the incoming phase.


Its amazing how things come you at 4am. What the hell am I doing up right now.:laughing:


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## 8V71

Yup....I layed down for a short nap after work and woke 8 hours later at like 2am. I hate that.


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## Cirus

I've been looking up stray voltage on the computer and it keeps coming up about problems with dairy barns. It says the #1 cause of stray voltage is the poco system.


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## Cirus

Getting off subject. How is work up north? Pretty bad down here.


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## 8V71

Well, I'm not an electrician but the company I have worked at for the past 18 years went belly up last year. New owners and I'm still there but...who knows what will happen next.


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## 8V71

I also wanted to comment on your lighting circuit but forgot. When I was taking about long runs I was mainly referring to the POCO primary. I also said secondary in my post but I was trying to include the neutrals running to the subs because I was thinking about the 4-wire theory. The long runs I mentioned don’t have anything to do with your lighting circuit.

How the POCO primary neutral can get raised. In a long run you have wire resistance (with voltage drop) and maybe an ok but not perfect connection or two thrown in as an extra, same difference. Since there is the same amount of current flowing on the primary neutral as in the hot conductor your load is trying to pull it up from ground. The wire resistance or poor connections allows this. Meanwhile, you have ground rods at the poles, transformer, ect. going into chitty non conductive soil trying to keep it at earth ground potential. I think this is what is happening when you turn one light on at a time and see the voltage slowly rising.


----------



## 8V71

Cirus said:


> I've been looking up stray voltage on the computer and it keeps coming up about problems with dairy barns. It says the #1 cause of stray voltage is the poco system.


Yeah, the livestock won't drink from the stock tanks because they feel the tingle. A fix is to elevate the ground voltage they stand on to the same potential as the tanks so they don't feel the voltage any more.


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## Cirus

I see what your getting at. It is a long primary run. Like I said earlier there is a good 1/2 mile of poles coming up through dense woods and the poles have been there for years. They just extended the line about 3 poles into the property. When it leaves the last pole it goes underground about 500 feet to the padmount then hits my service about 5 feet away. The engineer said something the other day about pole conductors or something. I remember when we first started talking about the job she said something about having to use that size of a transformer at that long of a run plus we are at the end of the line. We are on the tailend of the system. She acted like she wasn't to crazy about the setup.


----------



## Cirus

8V71 said:


> I also wanted to comment on your lighting circuit but forgot. When I was taking about long runs I was mainly referring to the POCO primary. I also said secondary in my post but I was trying to include the neutrals running to the subs because I was thinking about the 4-wire theory. The long runs I mentioned don’t have anything to do with your lighting circuit.
> 
> How the POCO primary neutral can get raised. In a long run you have wire resistance (with voltage drop) and maybe an ok but not perfect connection or two thrown in as an extra, same difference. Since there is the same amount of current flowing on the primary neutral as in the hot conductor your load is trying to pull it up from ground. The wire resistance or poor connections allows this. Meanwhile, you have ground rods at the poles, transformer, ect. going into chitty non conductive soil trying to keep it at earth ground potential. I think this is what is happening when you turn one light on at a time and see the voltage slowly rising.


So your saying that the poco my have a crappy neutral somewhere down the line and its trying to pick it up through my system or anywhere it can? If thats the case couldn't a homeowner nearby be experiencing the same situation?


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## 8V71

That's funny. I have a female POCO engineer and I'm doing the same at my property. But I'm trenching 1800' for underground primary feeding one pad mount and also at the end of the line.


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## Big John

Just out of curiosity, how many insulators are on the pole-top feeding your transformer? I imagine you only have one high voltage conductor, and one neutral a few feet lower?

In theory, the long neutral run shouldn't make a whole lot of difference, because the MGN is supposed to be re-grounded every 1/4 mile. Whether it was actually done, or whether those are in any good conduction might be another story.

-John


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## Cirus

One hot and one neutral then it goes underground. It is pure sand where I'm at. The guy thats owns the property sells dirt off the back side. He said he goes about 16 feet down before he runs out of dirt.


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## 8V71

Cirus said:


> So your saying that the poco my have a crappy neutral somewhere down the line and its trying to pick it up through my system or anywhere it can? If thats the case couldn't a homeowner nearby be experiencing the same situation?


Yes, but also they may be doing the best they can without driving sectionals. Just have to wait and see how much help they can give.

It could be happening with a homeowner but resi loads are normally much less than your lights so they might not see an issue.


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## Cirus

She seemed pretty concerned. I don't think I mentioned but whats bad is the guy who owns the track did all the work himself as far as buildings. The bathroom is where the problem first showed up. The bathroom is framed out of wood. The outside is covered in wood also but the inside walls are covered in sheetmetal all the way through with showers at one end. I think you know where I'm going with this. It ain't good. I have a few receptacles in the wall surrounded by this metal. I had to take tin snips and trim out around my boxes so the frame of my receptacles which are grounded, weren't touching the metal. When I did this the voltage dropped from 34 to near 0 from wet concrete to metal wall. Scary stuff.


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## hardworkingstiff

Cirus said:


> So your saying that the poco my have a crappy neutral somewhere down the line and its trying to pick it up through my system or anywhere it can? If thats the case couldn't a homeowner nearby be experiencing the same situation?


If their transformer is after the neutral issue (PoCo's neutral), yes (assuming that PoCo indeed has a neutral problem).


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## Cirus

Went out this morning and the head lineman was already there checking things out. He took readings at the padmount around all 3 secondary taps. With the lights on and minimal load at the concession and restrooms he got 386, 381, and 18 amps. He should have had around 5 on the neutral but not so. Puzzled the hell out of him. Th only real 120 load was two rvs that were hooked into the restroom panel. The ac units were running. Where was the other 13 amps coming from? It was like something offsite was putting on a load on the neutral. :001_huh:


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## hardworkingstiff

Cirus said:


> Went out this morning and the head lineman was already there checking things out. He took readings at the padmount around all 3 secondary taps. With the lights on and minimal load at the concession and restrooms he got 386, 381, and 18 amps. He should have had around 5 on the neutral but not so. Puzzled the hell out of him. Th only real 120 load was two rvs that were hooked into the restroom panel. The ac units were running. Where was the other 13 amps coming from? It was like something offsite was putting on a load on the neutral. :001_huh:


Did anyone put an ampmeter on the GEC (at the secondary neutral) at the transformer?


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## Cirus

He tried. I remember him trying to clamp around it but he said something about his meter being jacked up. He had two meters. The one that was giving him trouble was a clamp type. The other was a amp meter but not a clamp type. It was an open fork type with a big display. Thats what he used to get the amp readings from the 3 secondary taps.


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## Cirus

He also repaired some connections on 3 poles. 2 onsite and 1 offsite. He did say that the soil in that area was a bitch to locate stray voltage in. Said it would travel all over the place.


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## hardworkingstiff

Cirus said:


> He tried. I remember him trying to clamp around it but he said something about his meter being jacked up. He had two meters. The one that was giving him trouble was a clamp type. The other was a amp meter but not a clamp type. It was an open fork type with a big display. Thats what he used to get the amp readings from the 3 secondary taps.


I wonder why he didn't use the fork one to check the GEC.


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## hardworkingstiff

Cirus said:


> He also repaired some connections on 3 poles. 2 onsite and 1 offsite. He did say that the soil in that area was a bitch to locate stray voltage in. Said it would travel all over the place.


Did y'all have time to check the voltages after he made the repairs?


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## Cirus

Yep, no change. The 13 extra volts on the neutral had him baffled.


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## Cirus

hardworkingstiff said:


> I wonder why he didn't use the fork one to check the GEC.


I don't know. There was a copper clad rod driven. I saw that. The primary and secondary neutral were bonded to it.


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## hardworkingstiff

Cirus said:


> I don't know. There was a copper clad rod driven. I saw that. The primary and secondary neutral were bonded to it.


That's too bad, it may have answered the question.


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## 8V71

Cirus said:


> Went out this morning and the head lineman was already there checking things out. He took readings at the padmount around all 3 secondary taps. With the lights on and minimal load at the concession and restrooms he got 386, 381, and 18 amps. He should have had around 5 on the neutral but not so. Puzzled the hell out of him. Th only real 120 load was two rvs that were hooked into the restroom panel. The ac units were running. Where was the other 13 amps coming from? It was like something offsite was putting on a load on the neutral. :001_huh:


Good to see they are working on the problem.

Any other power users close by? Are you on city water or have any other grounded conductors coming in from the outside that your neutral is bonded to?


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## Cirus

8V71 said:


> Good to see they are working on the problem.
> 
> Any other power users close by? Are you on city water or have any other grounded conductors coming in from the outside that your neutral is bonded to?


There are a few homes close by. The closest one is maybe 500 yards. He is on county water. This place is about 15 miles from town and 1/2 a mile from the highway down a gravel road. There are quite few buildings up on the highway. The only thing coming into the property is water and power. 
No phone and no cable.


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## 8V71

The water line might be the next thing to look into. Someone might have a bad neutral and drawing off of yours.


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## hardworkingstiff

8V71 said:


> The water line might be the next thing to look into. Someone might have a bad neutral and drawing off of yours.


Since the current goes up/down with the light circuits on this property, I doubt it's a problem from a neighbor.


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## 8V71

hardworkingstiff said:


> Since the current goes up/down with the light circuits on this property, I doubt it's a problem from a neighbor.


Good point, but there are things that aren't making sense. Maybe there are multiple problems?

BTW Rodney....nice job on the how would you wire this thread. :thumbsup:


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## hardworkingstiff

Are there any other structures connected to this transformer?

If yes, it would be interesting to see if they have stray voltage problems when these lights are on.


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## Cirus

The only structures connected to this transformer are the ones I've mentioned. The concession and the restrooms. Everything feeds from the mdp. I'm going back out in the morning about dawn and take some more readings before it gets to hot. It takes two men to open the panel up and put it back together and I don't want to be doing it when its 105.


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## Cirus

The mystery here is where is the voltage coming from. The soil? The neutral? This is a long shot but if I could get the voltage up high enough I wondering if my Fluke pen tester would pick it? How low a voltage do they detect? Thats is when they work.:laughing:


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## hardworkingstiff

Cirus said:


> The mystery here is where is the voltage coming from. The soil? The neutral?


I'd bet $100 it's coming from the line side neutral that's bonded at the transformer to the load side neutral.

If you have time, with the lights on, check from ground (insert a metal probe a foot or so from the ground rod) to neutral (at the MDP), then again about 50' (with the metal probe) or so from the MDP. If I'm right, the voltage reading when you are 50' away is higher than it is when you are close to the ground rod because the ground rod is raising the ground to the neutral voltage and out a 50' the ground is not raised. 

I wonder if you could get a reading from two ground points 50' apart? If you do, I wonder if you could identify the source by moving the 50' points around to see where you get the highest readings, keep moving in that direction until you come to the source. Just an idea.


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## Cirus

Well, the poco lineman jabbed a screwdriver in the ground about 3' from the ground rod and checked between the two points and got 34 volts. I can get 34 volts from the concession 500' away. I got 43 volts the other day after it rained from dirt to disconnect frame at the bottom of one of my light poles and it was about 350' away.


----------



## hardworkingstiff

Cirus said:


> Well, the poco lineman jabbed a screwdriver in the ground about 3' from the ground rod and checked between the two points and got 34 volts. I can get 34 volts from the concession 500' away. I got 43 volts the other day after it rained from dirt to disconnect frame at the bottom of one of my light poles and it was about 350' away.


To me, this makes perfect sense with a PoCo neutral problem.


----------



## Cirus

Well, I took a couple of screwdrivers and at various points around the track took readings. The only place I could get anything was around the transformer and my service which are about 5' apart. The most I got was about 3.9 volts and that was between the padmount and service over the secondary. From rod to screwdriver I got around 34 with the ground wire attached or removed it didn't matter. Now, just for kicks I took my dual range pin tester and stabbed a screwdriver in the ground and got nothng. Now I went to some of my poles and the pin went of immediately when I got close to the disconnect. Every pole I went to did the same thing of course all my disconnects are bonded so that makes sense. The pin would go off when I got near the transformer or my service. I went to the restrooms 500' away and they have a compressor pluggged in and one of the guys said they got a tingle from the handle of the compressor the other night when the lights were on and he was wet. My pen also went off on the compressor handle today with the lights on and I got a reading of around 34 volts from it also to the concrete. The poco said they still weren't through. So thats where we stand.


----------



## wendon

Cirus said:


> Well, I took a couple of screwdrivers and at various points around the track took readings. The only place I could get anything was around the transformer and my service which are about 5' apart. The most I got was about 3.9 volts and that was between the padmount and service over the secondary. From rod to screwdriver I got around 34 with the ground wire attached or removed it didn't matter. Now, just for kicks I took my dual range pin tester and stabbed a screwdriver in the ground and got nothng. Now I went to some of my poles and the pin went of immediately when I got close to the disconnect. Every pole I went to did the same thing of course all my disconnects are bonded so that makes sense. The pin would go off when I got near the transformer or my service. I went to the restrooms 500' away and they have a compressor pluggged in and one of the guys said they got a tingle from the handle of the compressor the other night when the lights were on and he was wet. My pen also went off on the compressor handle today with the lights on and I got a reading of around 34 volts from it also to the concrete. The poco said they still weren't through. So thats where we stand.



I suppose you probably stated it earlier in the post but just a couple of questions. Does the voltage disappear when the main disco is shut off? Are all of the branch circuits 4-wired? I still think it's a POCO problem with a bad neutral connection or something of the like.


----------



## Cirus

wendon said:


> I suppose you probably stated it earlier in the post but just a couple of questions. Does the voltage disappear when the main disco is shut off? Are all of the branch circuits 4-wired? I still think it's a POCO problem with a bad neutral connection or something of the like.


Yes, voltage disappears when main is shut off. The voltage isn't an issue even when the main is on unless you apply a heavy load on the system. When the lights are off there is still minimal voltage on the system from the concession and restrooms but not enough to produce a shock. The 16 light poles are fed with 3 wire 240 volt. The lights are tapped 240 volt. The other 2 branch circuits are also 3 wire. With just the lights on you get 375 on each phase and 0 on the neutral. There is no unbalanced load when the lights are on. When the concession and bathrooms are on there is minimal load on the neutral. You can watch the voltage creep up as you turn the poles on.


----------



## 8V71

Cirus,

I'm not saying it's part of this problem but did you try unbonding the city water pipes from your system to help find that mystery current on your neutral?


----------



## Cirus

8V71 said:


> Cirus,
> 
> I'm not saying it's part of this problem but did you try unbonding the city water pipes from your system to help find that mystery current on your neutral?


Well, not that it matters but he is on county water with pvc coming into the property. There is no copper pipe in the slabs. They use around here what they call " pex " which is like flexible pvc.


----------



## hardworkingstiff

Cirus said:


> Yes, voltage disappears when main is shut off. The voltage isn't an issue even when the main is on unless you apply a heavy load on the system. When the lights are off there is still minimal voltage on the system from the concession and restrooms but not enough to produce a shock. The 16 light poles are fed with 3 wire 240 volt. The lights are tapped 240 volt. The other 2 branch circuits are also 3 wire. With just the lights on you get 375 on each phase and 0 on the neutral. There is no unbalanced load when the lights are on. When the concession and bathrooms are on there is minimal load on the neutral. You can watch the voltage creep up as you turn the poles on.


Well, I'm convinced it's a PoCo neutral problem, and since I'm convinced of this, I guess I'm blinded to any other possibilities until it's proven that the PoCo does not have a neutral problem.

I just with someone could take an amp reading on the conductor to the ground rod (inside the transformer housing, I'm assuming this is a pad mount transformer with a ground rod driven inside).

I would like to thank you Cirus for keeping us informed on the progress of this problem. I hope it gets fixed before someone really does get hurt.


----------



## Cirus

hardworkingstiff said:


> Well, I'm convinced it's a PoCo neutral problem, and since I'm convinced of this, I guess I'm blinded to any other possibilities until it's proven that the PoCo does not have a neutral problem.
> 
> I just with someone could take an amp reading on the conductor to the ground rod (inside the transformer housing, I'm assuming this is a pad mount transformer with a ground rod driven inside).
> 
> I would like to thank you Cirus for keeping us informed on the progress of this problem. I hope it gets fixed before someone really does get hurt.


Yes, there is a ground rod driven inside the padmount transformer. I'll saw that with my own eyes. The poco lineman did say that they usually only drive a 6' or 8' ground rod. He did say they might have to drive more rods. I also appreciate all the information and advice you guys have given me. I'll keep updating as I get more information.


----------



## frenchelectrican

Cirus said:


> Yes, voltage disappears when main is shut off. The voltage isn't an issue even when the main is on unless you apply a heavy load on the system. When the lights are off there is still minimal voltage on the system from the concession and restrooms but not enough to produce a shock. The 16 light poles are fed with 3 wire 240 volt. The lights are tapped 240 volt. The other 2 branch circuits are also 3 wire. With just the lights on you get 375 on each phase and 0 on the neutral. There is no unbalanced load when the lights are on. When the concession and bathrooms are on there is minimal load on the neutral. You can watch the voltage creep up as you turn the poles on.


I was reading this along the way and is those luminaire are 400 watts MH or PSMH ? or other wattage if I did miss it.

I am not sure if I did catch this one before or not but did you disconnect each luminaire and heat up the circuits to see if the voltage did creep up or stay the same.

There is a possiblty but I have no proof at the moment if you have ingitors tempory disconnect them or use the convental 400 w probe start luminaire with CWI ballast ( constat wattage isolated ) to see if that keep the voltage in check or creep up.

How hard the water it is from the ground ? 


Merci,
Marc


----------



## wendon

Cirus said:


> Yes, voltage disappears when main is shut off. The voltage isn't an issue even when the main is on unless you apply a heavy load on the system. When the lights are off there is still minimal voltage on the system from the concession and restrooms but not enough to produce a shock. The 16 light poles are fed with 3 wire 240 volt. The lights are tapped 240 volt. The other 2 branch circuits are also 3 wire. With just the lights on you get 375 on each phase and 0 on the neutral. There is no unbalanced load when the lights are on. When the concession and bathrooms are on there is minimal load on the neutral. You can watch the voltage creep up as you turn the poles on.


I'd suggest to the POCO that they install a isolation device on the transformer. They use them all the time on dairy farms to isolate the primary neutral from the secondary. If the problem goes away, you know it's on the POCO's side. They should be able to find the problem. A lot of them are nervous about finding problems on their system because of liability. You can't totally blame them with all the crazy lawsuits going on. It could be any one of a number of things on their system.


----------



## Cirus

frenchelectrican said:


> I was reading this along the way and is those luminaire are 400 watts MH or PSMH ? or other wattage if I did miss it.
> 
> I am not sure if I did catch this one before or not but did you disconnect each luminaire and heat up the circuits to see if the voltage did creep up or stay the same.
> 
> There is a possiblty but I have no proof at the moment if you have ingitors tempory disconnect them or use the convental 400 w probe start luminaire with CWI ballast ( constat wattage isolated ) to see if that keep the voltage in check or creep up.
> 
> How hard the water it is from the ground ?
> 
> 
> Merci,
> Marc


The lights are 1000w sports lighters. I have turned on a few of the pole circuits with the disconnects off at the bottom of the poles and there was no reading. We have hard water in our area


----------



## Cirus

wendon said:


> I'd suggest to the POCO that they install a isolation device on the transformer. They use them all the time on dairy farms to isolate the primary neutral from the secondary. If the problem goes away, you know it's on the POCO's side. They should be able to find the problem. A lot of them are nervous about finding problems on their system because of liability. You can't totally blame them with all the crazy lawsuits going on. It could be any one of a number of things on their system.


I was reading the other day about stray voltage on dairy farms and saw something about a isolation device but couldn't remember what it was called.


----------



## Big John

Cirus said:


> I was reading the other day about stray voltage on dairy farms and saw something about a isolation device but couldn't remember what it was called.


 My understanding is that's just a low voltage lightning arrestor between both windings, but I don't see how that would solve the problem: We pretty much know at this point that you're not seeing secondary current flowing on the earth. You can isolate the secondary all you want, and as long as you have a primary load, I think you'll have this problem.

-John


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## don_resqcapt19

Big John said:


> My understanding is that's just a low voltage lightning arrestor between both windings, but I don't see how that would solve the problem: We pretty much know at this point that you're not seeing secondary current flowing on the earth. You can isolate the secondary all you want, and as long as you have a primary load, I think you'll have this problem.
> 
> -John


As long as you can isolate the primary and secondary grounded conductors you should be able to eliminate the problem. The problem is not the current flowing on the earth, it is the elevated voltage of the grounded conductor as measured to the earth. Assuming the problem is with the primary grounded conductor and it sure sounds like it is, the isolation should eliminate the voltage between the grounded parts of the secondary side and earth.
I am not sure how you can do this isolation if the transformer is a pad mount. If the primary is not connected to the transformer case, you can't clear a primary fault. All of the uses of the "neutral blocker" that I have read about have been with pole mounted transformers.


----------



## Big John

I don't follow. 

I'm assuming at this point that what he's seeing is a voltage gradient caused by primary earth return current, agree or disagree?

I think the reason people are getting shocked is because he has conductive parts connected to areas of the earth that are at a distant part of the gradient, and so are at a different voltage relative to the point where the person is standing.

If that's true, he can isolate the the secondary from the primary, but he hasn't done anything to stop that current flow, because the primary is still connected to the MGN, and his grounded secondary system is still spanning that gradient.

EDIT: It just dawned on me how they'd be installing the arrestor: They're leaving a hard secondary connection, and putting the arrestor in the the primary side, which would in fact eliminate that earth return path. I'll grant that.

-John


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## wendon

don_resqcapt19 said:


> As long as you can isolate the primary and secondary grounded conductors you should be able to eliminate the problem. The problem is not the current flowing on the earth, it is the elevated voltage of the grounded conductor as measured to the earth. Assuming the problem is with the primary grounded conductor and it sure sounds like it is, the isolation should eliminate the voltage between the grounded parts of the secondary side and earth.
> I am not sure how you can do this isolation if the transformer is a pad mount. If the primary is not connected to the transformer case, you can't clear a primary fault. All of the uses of the "neutral blocker" that I have read about have been with pole mounted transformers.


They do install them on pad mounts. We upgraded a service last year on a farm that had a pole top transformer. They went to a pad mount transformer and installed an isolator on it. I think if the poco wanted to test this system, they could temporarily separate the primary and secondary neutral to test the voltage levels. If they're feeling a tingle there has to be a serious problem somewhere.


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## wendon

Big John said:


> I don't follow.
> 
> I'm assuming at this point that what he's seeing is a voltage gradient caused by primary earth return current, agree or disagree?
> 
> I think the reason people are getting shocked is because he has conductive parts connected to areas of the earth that are at a distant part of the gradient, and so are at a different voltage relative to the point where the person is standing.
> 
> If that's true, he can isolate the the secondary from the primary, but he hasn't done anything to stop that current flow, because the primary is still connected to the MGN, and his grounded secondary system is still spanning that gradient.
> 
> EDIT: It just dawned on me how they'd be installing the arrestor: They're leaving a hard secondary connection, and putting the arrestor in the the primary side, which would in fact eliminate that earth return path. I'll grant that.
> 
> -John


By installing the isolator, any return current from the primary side would have to return on the primary side neutral. Some would no doubt return on the grounds installed on the poles. (if they are installed)


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## don_resqcapt19

Big John said:


> I don't follow.
> 
> I'm assuming at this point that what he's seeing is a voltage gradient caused by primary earth return current, agree or disagree?


Disagree. He is seeing the voltage drop on the primary neutral as measured to earth. The earth is not energized, the grounded conductor is.
The energized primary neutral, in turn energizes everything that it is connected to. In this case it is connected to the secondary grounded conductor and the grounding conductors. All of these items become energized with a voltage that is equal to the voltage drop on the primary grounded conductor.


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## don_resqcapt19

wendon said:


> They do install them on pad mounts. We upgraded a service last year on a farm that had a pole top transformer. They went to a pad mount transformer and installed an isolator on it. I think if the poco wanted to test this system, they could temporarily separate the primary and secondary neutral to test the voltage levels. If they're feeling a tingle there has to be a serious problem somewhere.


So the metal parts of the pad mount are not connected to the primary grounded conductor?


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## wendon

don_resqcapt19 said:


> So the metal parts of the pad mount are not connected to the primary grounded conductor?


I haven't paid that much attention to them but I think they remove the ground strap. If you look at this site it has some pics etc.

http://fyi.uwex.edu/mrec/files/2011/03/tachick-Dairyland-Isolators.pdf


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## 8V71

wendon said:


> I haven't paid that much attention to them but I think they remove the ground strap. If you look at this site it has some pics etc.
> 
> http://fyi.uwex.edu/mrec/files/2011/03/tachick-Dairyland-Isolators.pdf


Very helpful information. :thumbsup:


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## frenchelectrican

Cirus said:


> The lights are 1000w sports lighters. I have turned on a few of the pole circuits with the disconnects off at the bottom of the poles and there was no reading. We have hard water in our area


There something I may think it may I will not say 100% but what type of conductor you did have it ran underground ?

I am thinking induction of current cause stray voltage to show up. senice you mention you did disconnect at bottom of the luminaire pole so that pretty much rule out induction voltage at the point but once you put a load on sorta like a tunning fork or something like that can cause to make a stray voltage. ( sorta like a monster current transfomer ) 

The only way you can kill them pretty good is have braided cable I know it will be nuts to hear that but that can slove it otherwise I wish you should use our European cable what we called SWA ( steel wire armoured cable ) that useally kill that issue what you have there.

Merci,
Marc


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## donaldelectrician

8V71 said:


> Very helpful information. :thumbsup:




I did not know COWS are ratted at 500 OHMS !



Don


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## hardworkingstiff

frenchelectrican said:


> There something I may think it may I will not say 100% but what type of conductor you did have it ran underground ?
> 
> I am thinking induction of current cause stray voltage to show up. senice you mention you did disconnect at bottom of the luminaire pole so that pretty much rule out induction voltage at the point but once you put a load on sorta like a tunning fork or something like that can cause to make a stray voltage. ( sorta like a monster current transfomer )


How would that raise the voltage between the grounded conductor and the earth?


> The only way you can kill them pretty good is have braided cable I know it will be nuts to hear that but that can slove it otherwise I wish you should use our European cable what we called SWA ( steel wire armoured cable ) that useally kill that issue what you have there.
> 
> Merci,
> Marc


Are you saying that using this SWA cable can take care of PoCo degraded neutral connection on the primary feeding the transformer?


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## Cirus

If this is a bad primary neutral connection or voltage drop on the neutral as some have said what is the cure? What if the poco can't find the problem? What if it is voltage drop, what would they have to do about that?


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## frenchelectrican

hardworkingstiff said:


> How would that raise the voltage between the grounded conductor and the earth?


I know this is a instering sisutation unfolding here and I am pretty sure the OP did mention hardwater sorta like very high on iron level when you engerized the conductor without a load on it do not much at all but once you put a load on it can induct the voltage by running the current sorta like electromagtic.

If he have soft water or hard water without iron in the water none of those can happend.





hardworkingstiff said:


> Are you saying that using this SWA cable can take care of PoCo degraded neutral connection on the primary feeding the transformer?


Yeah it can take care of it and I do not know which type of underground cable the OP is useing from overhead primary to underground secondary but let be safe to assumed that they did used coneracted netural aka copper netural wrapped conductor type. if that was nicked some reason it can happend.

For the secondary side I am pretty sure it will prevent the situation unfolding like that but costwise I know they are not cheap but if used correct way, It can be justifed.

I will post the photo of SWA cable so you get the idea.










They do come in various size and I know you don't have them much in state side but correct me if I am wrong if they do use them ( I know not very wide spread useage in North American side ) but it is common over here.

For the rest of the answer I will wait until Cirus reply with confirmed answer on this one.

Merci,
Marc


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## frenchelectrican

Cirus said:


> If this is a bad primary neutral connection or voltage drop on the neutral as some have said what is the cure? What if the poco can't find the problem? What if it is voltage drop, what would they have to do about that?


As far for the voltage drop on primary side they can able adjust it without major issue so they have some leeway with it.

Now for Netural issue what you are going thru are they ran it in single phase or triphase primary ? but what if the POCO change the connection on that spur to P-P format ( primary to primary ) format it may reduce the amount of stray voltage show up but I do not know if they will justify the cost to convert it. If that is a single phase primary but three phase it can go either way depending on how they hook up the transfomer(s).

Keep us updated if you find out more about it. 

Merci,
Marc


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## Cirus

frenchelectrican said:


> Now for Netural issue what you are going thru are they ran it in single phase or triphase primary ?
> 
> Merci,
> Marc


Single Phase. Two wires. One hot and one neutral overhead then 500' underground to padmount transformer.


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## hardworkingstiff

Sorry frenchy, but I disagree. SWA cable on the secondary side will not help things if the problem is a deteriorating primary grounded conductor connection (anywhere on the line) causing excessive voltage drop that is finding its way onto the secondary grounded conductor. :no:


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## wendon

Cirus said:


> If this is a bad primary neutral connection or voltage drop on the neutral as some have said what is the cure? What if the poco can't find the problem? What if it is voltage drop, what would they have to do about that?


Good question!!! As long as your not having a problem with voltage fluctuation (dimming lights etc.) I'm not sure what they *have* to do.
Depending on what type of poco you have. I would think most of them would want to resolve an issue like this. It may mean running heavier conductors etc. It would be interesting to know what kind of amperage (milliamps?)you have on all of your grounding electrode conductors. You should be seeing some return on all of them. Another thing would be nice if you had a data logging meter, scope etc. where you could get a hard copy of your findings.
Another thing they can do is to up the voltage on their primary but that might not be practical.


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## Spark Master

Who's paying for all your hours dealing with this ??? And all the phone work with the poco.


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## Cirus

Spark Master said:


> Who's paying for all your hours dealing with this ??? And all the phone work with the poco.


No one. I really haven't invested that much time in it. Hell, I've spent more time talking to you guys than I have with the poco. I've made a few trips out there in my spare time but not taking off work to do it. I just want to be assured that its not a problem on my end, which I feel certain that its not. I don't want someone getting a shock and then running me down to everyone when its not my fault. Just covering my ass. I hung out with the head lineman last week out there for several hours helping him look for the problem and he all but admitted that it was there problem. 
.


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## Electric_Light

Cirus said:


> Yea, my meter is not big enough to clamp around all the conductors on my side. May have to get the poco to open up the meter base. I assume they paralleled the secondary but I wasn't there when they did the work. I've got 4 conductors per phase on my side.


Wire in a 240v GFCI in series. GFCI is a differential amplifier. It the current in both wires do not cancel out perfectly, it will trip it.


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## hardworkingstiff

Electric_Light said:


> Wire in a 240v GFCI in series. GFCI is a differential amplifier. It the current in both wires do not cancel out perfectly, it will trip it.


What are we trying to accomplish with this?


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## Cirus

Electric_Light said:


> Wire in a 240v GFCI in series. GFCI is a differential amplifier. It the current in both wires do not cancel out perfectly, it will trip it.


No need for this. I've since bought a meter to check mutiple conductors.


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## hardworkingstiff

Cirus said:


> No need for this. I've since bought a meter to check mutiple conductors.





Cirus said:


> Went out this morning and the head lineman was already there checking things out. He took readings at the padmount around all 3 secondary taps. With the lights on and minimal load at the concession and restrooms he got 386, 381, and 18 amps. He should have had around 5 on the neutral but not so. Puzzled the hell out of him. Th only real 120 load was two rvs that were hooked into the restroom panel. The ac units were running. *Where was the other 13 amps coming from?* It was like something offsite was putting on a load on the neutral. :001_huh:


So with your new meter you come across the extra amps again, then what?

I'm sure glad it's you doing this and not me, :laughing: , because I'd be very frustrated by now. 

Did the PoCo ever figure out where the 13-amps was coming from or going to? Here's the thing, if it was coming from the primary grounded conductor to the ground rod then back up the GEC inside the transformer to the secondary grounded conductor and out of the transformer how would you know?


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## Electric_Light

hardworkingstiff said:


> What are we trying to accomplish with this?


You find another meter that will clamp onto two wires and effectively detects <0.05A difference accurately. 

They do have mA type meter, but they're big $$$ for something not used often.


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## hardworkingstiff

Electric_Light said:


> You find another meter that will clamp onto two wires and effectively detects <0.05A difference accurately.
> 
> They do have mA type meter, but they're big $$$ for something not used often.


They already tested the conductors at the transformer secondary and found a 13-amp imbalance on the grounded conductor. They know there is a difference.


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## Cirus

I wonder, if the poco did have a voltage drop problem would it show up even with minimal load applied on the system? I mean, I can turn on just one pole and the voltage starts to develop. I can see it if several poles are on but just one pole? I did energize several of the pole circuits but turned off the disconnects at the bottom of the poles and there was no voltage until I turned the disconnects on and load was applied. Out of curiousity I went to a pole and disconnected the load side neutral/ground that goes up the pole to see if the voltage might be manifesting itself in the lights and somehow traveling down the n/g to the disconnect. No difference. Voltage remained. Oh well.


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## hardworkingstiff

As the load increases on the secondary the current increases on the primary of the PoCo transformer. So, it makes sense that as you increase the load the VD on their grounded conductor goes up.

Now, if you want to test this theory and have a load bank, you can hook the load bank directly to the transformer secondary (or even the MDP 5' away) and if the problem is a PoCo VD, then as you increase the load on the load bank the stray voltage should increase.

What do you think?


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## wendon

hardworkingstiff said:


> As the load increases on the secondary the current increases on the primary of the PoCo transformer. So, it makes sense that as you increase the load the VD on their grounded conductor goes up.
> 
> Now, if you want to test this theory and have a load bank, you can hook the load bank directly to the transformer secondary (or even the MDP 5' away) and if the problem is a PoCo VD, then as you increase the load on the load bank the stray voltage should increase.
> 
> What do you think?


I think that's a good idea if you can get the PoCo to do it and leave the secondary neutral hooked up to the rest of the service so you can check the voltage at various points.


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## Cirus

Here is something think about. As an experiment I drove 3 more rods at the mdp. One at every corner of the H frame. I run a #6 bare from rod to rod making a complete loop around my service. I turned on the lights and the voltage started to climb but not like before, much slower. When everything was heated up I had about 22 volts at the mdp and the padmount transformer. I still had the around 37 at the poles though. So I knocked it down about 15 volts at my service but no where else. Any thoughts? A electrician buddy of mine said he dealt with the same thing on a job and the poco never did find it. He said he bet the poco will just say they can't find it and give up and they probably won't come right out and say its there problem just to cover there ass. He said they had no choice but to pound rods until it went away. This a different poco though.


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## hardworkingstiff

Did you by any chance take an amp reading on that #6 leaving the panel?

I think you raised the ground potential around the MDP a little by driving those rods. 

As far as your buddy's comments, I agree, I fully expect the PoCo will come back and say everything checked out OK.

I still think you need to try to isolate the GEC from the secondary neutral inside the transformer and see what happens with the stray voltage. I don't know if the PoCo will cooperate though.


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## don_resqcapt19

hardworkingstiff said:


> ...
> I think you raised the ground potential around the MDP a little by driving those rods. ...


That is exactly what happened and is why you can't solve this type of problem by adding additional grounding electrodes. 

If you have a lot of time and money, you could install a grounding grid with the legs of the grid about 6" to a foot apart over the whole area and raise the voltage of the whole area to match that of the primay neutral:no:

The utility needs to solve the problem on their primary. Maybe it is time to get the state utility commission involved.


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## hardworkingstiff

don_resqcapt19 said:


> Maybe it is time to get the state utility commission involved.


:thumbsup:

I think Don is correct. Maybe not just yet, but pretty soon.


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## Cirus

hardworkingstiff said:


> Did you by any chance take an amp reading on that #6 leaving the panel?
> 
> I still think you need to try to isolate the GEC from the secondary neutral inside the transformer and see what happens with the stray voltage. I don't know if the PoCo will cooperate though.


Yep, .5 of an amp

I'll mention it to them when they show back up.


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## guest

hardworkingstiff said:


> .... found a 13-amp imbalance on the grounded conductor. They know there is a difference.





hardworkingstiff said:


> As the load increases on the secondary the current increases on the primary of the PoCo transformer. So, it makes sense that as you increase the load the VD on their grounded conductor goes up......





Cirus said:


> .... I turned on the lights and the voltage started to climb but not like before, much slower. When everything was heated up I had about 22 volts at the mdp and the padmount transformer. I still had the around 37 at the poles though. So I knocked it down about 15 volts at my service but no where else. .....



Have the POCO test the padmount transformer thoroughly. I suspect that they will find one of the following:

Internal fault in the primary winding;
Primary winding neutral connection in the transformer tank loose;
Secondary XO connection loose in the tank.

See if they can bring another transformer out as a temp for testing.


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## Nukie Poo

Whats the latest on this issue?


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## oldtimer

Nukie Poo said:


> Whats the latest on this issue?


 
NUKIE POO ! 

I just have to ask ... ... are you kin to HONEY BOO-BOO ?

:laughing::laughing:


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## Cirus

Nothing new to tell. The poco is still working on it. One thing for sure they know its on their system. A guy was out there last Saturday night and leaned up against one of the poco poles where the bare copper comes down and got a shock. I called the poco and let them know.


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## kbsparky

Sounds like a bad concentric conductor on a primary ...


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## Hippie

oldtimer said:


> NUKIE POO !
> 
> I just have to ask ... ... are you kin to HONEY BOO-BOO ?
> 
> :laughing::laughing:


Ahhaahaa


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## Meadow

Keep fighting the utility, Ive done it before on all sorts of issues, yes they can be stuborn,but it does pay off.

If they cant get it fixed, like others have said go to the commission. :thumbsup:


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## Nukie Poo

Hippie said:


> Ahhaahaa


Who's Honey Boo Boo? Is that from that stupid Toddlers and Tiaras?


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## Hippie

Nukie Poo said:


> Who's Honey Boo Boo? Is that from that stupid Toddlers and Tiaras?


I think so, I see previews for it all the time when I'm trying to watch Hoarders. They look like a gross family of inbreds


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## Nukie Poo

meadow said:


> Keep fighting the utility, Ive done it before on all sorts of issues, yes they can be stuborn,but it does pay off.
> 
> If they cant get it fixed, like others have said go to the commission. :thumbsup:


Let me guess, Cirus: are you on Long Island? Ever since Nat'l Grid bought out Keyspan, getting to even talk to someone is like pulling teeth. Btw, I have trick for getting quick responses in an emergency: I just tell them the customer has an in-dialysis machine. Works everytime. You just cant over use it.


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## Nukie Poo

Cirus said:


> Nothing new to tell. The poco is still working on it. One thing for sure they know its on their system. A guy was out there last Saturday night and leaned up against one of the poco poles where the bare copper comes down and got a shock. I called the poco and let them know.


I'll tell ya, if it is indeed a bad N on the primary - which is what I suspect it is - I'd be real careful about lifting GECs and EGCs. But, from what I've read here, its kinda too late :-/ If it were me, I'd red tag the place until this is fixed. You'll piss people off but its the right thing to do. This could get worse and someone could get hurt. If that, God forbid, were to happen, I would definitely not want to be the electrician of record. Besides, the acrimony that is sure to follow a red tag mighy hasten things along. Just my $0.02


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## hardworkingstiff

Cirus said:


> Nothing new to tell. The poco is still working on it. One thing for sure they know its on their system. A guy was out there last Saturday night and leaned up against one of the poco poles where the bare copper comes down and got a shock. I called the poco and let them know.


Well, it's been over 2 months. Any update? How did this end? Is it fixed?


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## jza

Interesting


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## stubs

sounds like one of your hot conductors is leaking to ground??????


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