Understanding Stray Voltage

[Industrial Toys]

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.

 

[oldnslo]

Are there any high voltage overhead lines in the area of this barn. I am talking about main transmission lines and not rural transmission lines. Reason for asking is that was a problem for Dairy farms in Minnesota after they ran a new high voltage transmission line through the area. If I recall correctly is was in the 400 KVA range.

I do not recall what all had to be done to eliminate the stray voltage problems.

 

[Industrial Toys]

Thanks. No, just the 3800 single phase coming in and it's as far away from the barn as it could be.

 

[oosik]

Hmmm - many years ago a horse I had would not drink out of the water trough. The trough was a 55 gallon plastic barrel - on its side and cut open. Had a tank heater in the barrel. Everything was grounded according to code. Horse would bend down to drink - lips would start quivering and she would back off. Took the tank heater out - still no joy.

Soooo........tank heater back in water trough - 2x daily - scoop water out of trough with plastic 5 gallon pail - horse would gratefully drink out of 5 gallon pail. At the time - thought horse was Norwegian like me and just stubborn. Maybe it had something to do with water trough being directly under high voltage lines bringing power into house and out buildings.

Maybe horse WAS Norwegian, like me, and just stubborn - - who knows.

 

[Industrial Toys]

When this house was built in the early 70s, you would get zapped touching the shower controls in the basement, on cement shower. A volt meter between metal knobs and drain would confirm this.

Had an army of Ontario Hydro inspectors and Electricians in. Everything to code, just live with it! I always used my palms and made my adjustments quickly. I was contemplating putting in plastic shower knobs.

Anyway, it SEEMS that when I replaced the water heater years later, the problem went away.

I never really thought about it, but reading up on this stuff I learned that concrete is a better conductor than soil.

 

[CADplans]

My BIL had that at his shop,,,
it shocked everyone for years,, whenever the soil got dry,,,

I went hunting it, it turned out to be a loose connection of the ground at the box that fed the shop, 150 yards away,,,

Two turns of a screwdriver, the ground/shock problem was eliminated.

That was all copper, as the shop was old,,,
new stuff, with aluminum wire, can easily have a loose/corroded connection,,,

 

[Industrial Toys]

I had driven the ground rod with a hydraulic breaker and made quite a hole, hitting bedrock with about a foot to go. So I thought, maybe the ground rod was making poor earth contact. First I tamped dirt into the hole, with no improvement and then poured a couple of pails of (hard) water. Not one volt difference from the 7 volts, electrical ground to the tin!

For what it's worth, he does have a solar microfit installation on a shed close to the house.

 

[CADplans]

I had driven the ground rod with a hydraulic breaker and made quite a hole, hitting bedrock with about a foot to go. So I thought, maybe the ground rod was making poor earth contact. First I tamped dirt into the hole, with no improvement and then poured a couple of pails of water. Not one volt difference from the 7 volts, electrical ground to the tin!

For what it's worth, he does have a solar microfit installation.

The ground rod, IMHO, should not make a difference,, it is there more for a safety/emergency purpose,,,

The ground wire(s) from the box feeding the outlet being used should be grounding the circuit.

Disconnect the ground rod (temporarily),,, the disconnection should make no difference in the voltage measured.

Measure the voltage at the other end of the ground wire,,,

 

[JPRambo]

Is the feed to the barn 240 volts? Does the feed to the barn have four wires? Is the trough heater 120 volt or 240 volt?

 

[RNeumann]

You need to go back to the panel and start there with your meter. Systematically isolate each wire to see where the voltage is coming from. A circuit, the main/service to the barn etc. If the barn has multiple circuits they should all be off to start.
It’s likely something got pinched or chewed in the barn. Second is an underground line. Etc etc.

 

[Industrial Toys]

Sorry, I am a bit confused. Basically, anything that has an earth ground at the barn will see a potential if contacting electrical ground. So, I figured, effectively shorting that to ground locally with a rod would help.

 

[HickoryFarms]

A neutral wire is the return path for stray voltage, which will go to ground if grounded properly. I’d check all of my ground and neutral connection on your side, making sure everything is clean and tight. A poor or open neutral on the utility’s side can cause this to occur as well. Often actually.

 

[CADplans]

Sorry, I am a bit confused. Basically, anything that has an earth ground at the barn will see a potential if contacting electrical ground. So, I figured, effectively shorting that to ground locally with a rod would help.

No, the ground rod should not be a functional part of the electric circuit,,,

 

[HickoryFarms]

So, I figured, effectively shorting that to ground locally with a rod would help.

It certainly should.

 

[CADplans]

Sorry, I am a bit confused. Basically, anything that has an earth ground at the barn will see a potential if contacting electrical ground. So, I figured, effectively shorting that to ground locally with a rod would help.

Back in the 1950's, my father used to bring home ground rods the phone company used,,
they were, if I remember correctly,,, made out of bronze.

A steel ground rod is almost useless in dispersing any amount of current,,
that is why you will see a voltage when using a ground rod for the ground.

Steel easily develops a resistive surface,, that is why you will see the 7 volts to the ground rod.
I assume the ground rod is steel. Even copper coated steel is a poor conductor,,,

 

[HickoryFarms]

Back in the 1950's, my father used to bring home ground rods the phone company used,,
they were, if I remember correctly,,, made out of bronze.

A steel ground rod is almost useless in dispersing any amount of current,,
that is why you will see a voltage when using a ground rod for the ground.

Steel easily develops a resistive surface,, that is why you will see the 7 volts to the ground rod.
I assume the ground rod is steel. Even copper coated steel is a poor conductor,,,

We use stainless steel ground rods for for “important” stuff, and copper coated steel ground rods for everything else at the utility I work for.

 

[Industrial Toys]

It's just galvanized. I plan on sticking a (test) copper ground rod outside the house and with a long wire see if I get voltage between the U ground of any given recepacle and the rod. I am guessing I do. They probably have the same issue at the house, just never realized it.

Ever try and help someone out?

 

[CADplans]

We use stainless steel ground rods for for “important” stuff, and copper coated steel ground rods for everything else at the utility I work for.

Hmmmmm,,,,,,,, stainless is an interesting material,, the amperage would become important when using stainless.

 

[GLyford]

While doing due diligence to trace the issue is definitely worth the time, the problem might not be in your local install.

A dairy my brother worked for had a stray voltage problem. Turns out the utility used the poles themselves as the center tap reference connection for the transformers and the resistance of the wood was enough to create about 5 to 7v voltage drop from the top of the pole to the dirt at the bottom. Especially if the phase loads on the transformer are not balanced (odd number of houses, whatever), the earth can still be carrying current back to and even through the poles.

Solution was to have the utility put a return ground wire on every pole near the farm. Five years later, the utility replaced all their poles on that street, and all those ground wires ended up on the truck. Farmer had to call them out to do it again.

One town I lived in for a while had a community owned electric company, and didn't use that system, they spent the money to run the extra return conductor instead...I was talking to the crew in the bucket truck as they replaced the connection outside my 2nd floor window. No idea which system is used at my current place since the lines are underground, but since the transformer is on a pad at least there is no pole resistance.

 

[RNeumann]

I don’t believe you are going to ground rod your way of this.......

You need to diagnose before you attempt to fix it.