Understanding Stray Voltage

[MossRoad]

I am trying to help a neighbor. The cattle were not drinking from a pail with an approved heater. I gave him another brand new heater, same thing. I measured some voltage, from the ground of the receptacle to some tin on the shack leading into the barn.

I installed a temporary cheater plug, removing the ground and for the time being, the animals drank from the pail.

I noticed there was no ground rod at the barn. The barn is fed underground from a house panel a hundred yards away.

We installed a ten foot ground rod at the barn. I was shocked (pun intended) to still see 7 volts between electrical ground and the tin on the building. That tin is apparently in good contact with Earth Ground.

I understand electrical stuff, and have tried reading up on tingle voltage and stray voltage, but I really don't understand what's happening. Or how to correct it. There are Reactor Filters, which are apparently now seldom used anymore and hence no longer made by Hammond, but I understand that even less.

Is there a panel in the barn or is it just one circuit from the house to the barn?

If there's a panel, it should be set up as a sub-panel from the house. The neutral and ground should not be connected together anywhere except the main panel. Is that the way it's set up?

 

[Ken]

Is there a panel in the barn or is it just one circuit from the house to the barn?

If there's a panel, it should be set up as a sub-panel from the house. The neutral and ground should not be connected together anywhere except the main panel. Is that the way it's set up?

Can you contact the Electric Utility company and ask for a voltage check and explain the stray voltage to ground .

Look for a pipe line underground or rail road using catalytic voltage to protect the metal . then look at what is in the barn using voltage. Milk parlor vacuum pumps chillers for the milk cooling and water tanks with heaters.

When I was searching for this type of problems even a electric fence will cause stray voltage. One time the farmer put a battery charger on "H" Farmall to have fully charged battery to start on cold morning . it had a one side ground to outlet and he had plugged it rolled over so the tractor was at line voltage. rubber tires kept the circuit from tripping. Next morning first step on tractor gave him a unexpected kick.

Start at main Breaker and if reading voltage to ground keep shutting off breakers until located or remains reading it will be the power co feeding the voltage. High humidity in barns and breaker panels can cause a reading .

If your ground at main continue to have a current flow adding salt deep as can be dug will attract moisture to develop
a power ground to earth.
horses and cattle feel the different potential between the front feet and rear feet. some will not return to barn if shocked by this.
it will surprise you what you find usually totally unexpected
ken

 

[Industrial Toys]

Thanks.

It is a two circuit "fuse" panel. The neutral and ground are not connected in that panel.

Do sub panels like that require a ground rod by code?

I had shut off the main switch in the barn and found no difference in the reading. He does have a fencer, but that would give readings on and off in time with the HV o/p, no? Maybe I am missing something with that.

I shuddered when I saw one of those screw in breakers in place of one fuse. I imagined hearing sirens some night and seeing the sky ablaze! I do think fuses were much safer than breakers, except people could do stupid and unsafe things with them. But that's another topic.

 

[HickoryFarms]

Thanks.

It is a two circuit "fuse" panel. The neutral and ground are not connected in that panel.

Do sub panels like that require a ground rod by code?

I had shut off the main switch in the barn and found no difference in the reading. He does have a fencer, but that would give readings on and off in time with the HV o/p, no? Maybe I am missing something with that.

I shuddered when I saw one of those screw in breakers in place of one fuse. I imagined hearing sirens some night and seeing the sky ablaze! I do think fuses were much safer than breakers, except people could do stupid and unsafe things with them. But that's another topic.

The neutral that is on the line side of that panel, what is it doing on the other end?

 

[Industrial Toys]

I suspect it is on the Neutral buss of the main panel in the house. NMW 10/3, House Panel to Barn Panel (2 circuit fused disconnect switch) underground 100 yards unbroken (fairly new cable).

FWIW I get no voltage between neutral and ground at the barn panel.

 

[HickoryFarms]

I suspect it is on the Neutral buss of the main panel in the house. NMW 10/3, House to Barn underground 100 yards unbroken (fairly new cable).

FWIW I get no voltage between neutral and ground at the barn panel.

Are you getting good voltage phase to neutral?

 

[pmsmechanic]

Just here to learn something.

 

[Industrial Toys]

Not sure I measured phase to neutral.

I am still trying to get my head around this. Essentially getting shocked by the ground conductor.

I was thinking though. That fencer. If it had a coupling capacitor neutral to ground or a failed MOV (Lightning Protection) Neutral to ground, it COULD put some voltage on the ground at the far end of a long run IF the neutral was not balanced. And shutting off power at the barn would not stop that, only unplugging the fencer which I don't even know where it is.

 

[HickoryFarms]

Not sure I measured phase to neutral.

I am still trying to get my head around this. Essentially getting shocked by the ground conductor.

I was thinking though.

An open neutral does weird things. I’ve drawn an arc off an open neutral putting it back together before. Of course that what 12 thousand volt primary voltage, but the same concept applies to secondary. If a phase was rubbing somewhere, you shouldn’t just be getting 7 volts. You would likely be getting 120 volts. Remember a neutral is the return path for stray voltage in a WYE type system. If you have an open neutral, or poor grounds, and are getting 7 volts on the tin, that stray voltage that is generally returned to earth via a grounded neutral, is just waiting for a path to ground. Hence the reason you can measure voltage from the tin to ground.

A capacitor stores voltage and releases upon demand, so it should not be wired into the ground and neutral, and a lighting arrestor is wired phase to ground. They can possibly leak, but generally they just blow.

 

[Industrial Toys]

I (believe) I have seen two prong devices that used a coupling capacitor to use the ground afforded by the neutral. I could be very wrong about that.

That switch is very tight and congested, so I don't like the idea of messing with it again. But I wish I had taken some measurements while the three circuits in the barn had the neutrals off.

So, IS a ground rod, code for a sub panel? One, or more?

 

[HickoryFarms]

I (believe) I have seen two prong devices that used a coupling capacitor to use the ground afforded by the neutral. I could be very wrong about that.

That switch is very tight and congested, so I don't like the idea of messing with it again. But I wish I had taken some measurements while the three circuits in the barn had the neutrals off.

So, IS a ground rod, code for a sub panel? One, or more?

I believe it is, unless you have a steel pipe going underground from the sub panel, then that can count as your ground. Codes definitely vary locally.

 

[Industrial Toys]

So, just to be clear.

You can't bond the neutral and electrical ground at the sub panel. And I am guessing that it's a safety concern that if you broke the neutral, the ground conductor. would assume that role.

So taking things one step farther. If a device in the barn had neutral and electrical ground tied together, that would be the same as it being bonded at the panel, but would not cause the problems being experienced. Or?

 

[HickoryFarms]

So, just to be clear.

You can't bond the neutral and electrical ground at the sub panel. And I am guessing that it's a safety concern that if you broke the neutral, the ground conductor. would assume that role.

So taking things one step farther. If a device in the barn had neutral and electrical ground tied together, that would be the same as it being bonded at the panel, but would not cause the problems being experienced. Or?

Neutrals get grounded. In my sub-panels, the neutrals are going to lugs affixed to the panel (they aren’t isolated lugs like the phases), and the panel is grounded. The stray voltage on a neutral gets sent to earth.

 

[aczlan]

Neutrals get grounded. In my sub-panels, the neutrals are going to lugs affixed to the panel (they aren’t isolated lugs like the phases), and the panel is grounded. The stray voltage on a neutral gets sent to earth.

That is not correct per the current NEC. The most recent NEC requires that any sub-panels have the neutrals isolated and the only place where the neutrals and the grounds are connected is at the first is connection point (which is generally your primary breaker panel).
Hence, per the current NEC you should have two hots, a neutral and a ground going from the main panel to any and also panels including sub-panels in remote buildings.

Aaron Z

 

[JPRambo]

If a device in the barn had neutral and electrical ground tied together
If this was true you would be replacing fuses when the device was turned on.
What is in the barn that is connected to this panel? Fluorescent lights? Outlets used for?

 

[Doofy]

Noticed a tingle when barefoot on the concrete garage floor (kids and dog actually told me this). The kids hollered and the dog wouldn't even go in. I went thru the panel and all the lighting fixtures and receptacles to no avail. Finally, tracked the problem down to the garage door opener. There were a couple of small lighting arrestor type small capacitors (or something) that had one blown. I cut them both off and no more tingle.

 

[JPRambo]

Glad you found the problem.

 

[teejk]

That is not correct per the current NEC. The most recent NEC requires that any sub-panels have the neutrals isolated and the only place where the neutrals and the grounds are connected is at the first is connection point (which is generally your primary breaker panel).
Hence, per the current NEC you should have two hots, a neutral and a ground going from the main panel to any and also panels including sub-panels in remote buildings.

Aaron Z

You are referring to "single point grounding" (meaning all grounds come back to the primary ground at the service entrance...usually the main breaker box)? It's a confusing concept I guess. E.g. satellite TV is supposed to come back to that point but if you ask any installer he'll ignore you while he sinks his separate ground rod (cheaper than running 6ga wire I guess).

 

[HickoryFarms]

That is not correct per the current NEC. The most recent NEC requires that any sub-panels have the neutrals isolated and the only place where the neutrals and the grounds are connected is at the first is connection point (which is generally your primary breaker panel).
Hence, per the current NEC you should have two hots, a neutral and a ground going from the main panel to any and also panels including sub-panels in remote buildings.

Aaron Z

I’m honestly not familiar with too much residential codes. Relying on one single connection for your ground doesn’t make much sense to me. But if that’s what it is......

If a device in the barn had neutral and electrical ground tied together
If this was true you would be replacing fuses when the device was turned on.
What is in the barn that is connected to this panel? Fluorescent lights? Outlets used for?

Every 3rd pole we set, the neutral gets grounded to the earth. I would presume most utilities throughout the country have a WYE, multi grounded system. The same goes for our secondary voltages (the stuff that powers your house), the neutrals are grounded.

 

[John Fitzgerald]

See "step potential".