Stray Voltage

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roger said:
It is a fact that very low currents will affect livestock. See 547.9 taking note of the FPN to 547.9(C)

Then read 547.10.

Knowing that you frequent Flukes website, Fluke had a newsletter/case study on this a while back.

Roger
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I have read that reference before. I have no experience in this, and I am surprised at what level this is of concern. Thank you Roger for the reply. I googled this and I was surprised on how many relations there were.


"You big dummy!" Yeah, that's me:roll: I told you all I earned the signature:cool: Learning something new all the time. Problem is,.... I should of googled this ahead of time.


Wrong again,.......:roll: DUMMY!!!!:D
 
benaround said:
bro, What happens when you disconnect 'all' the ground rods from the metal drinking bowl?

How did you turn off power to the heater, unit switch on heater or disconnect the cord

from the recpt?? Is there an EGC with the circuit conductors that supply power to the

heater?? Could the heater be defective and be 'leaking' this current??
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I have went so far as to pull the meter socket at the house and I still have the 5 volts... So I figure it has to be bleeding from somewhere... With having plastic pipe from the well to the waterer it makes it tough to ground...
 
mdshunk said:
Let me guess... these waterers have heaters in them, right? If not, we'll go on to the more complicated step 2.

99% of the time, the "stray" voltage is from stuff right on your own farm.
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Yes they do have heaters under the bowl. It stays outside of the water... I have unplugged the circuit to the waterer, still 5 volts. I turned off the barn panel, still 5 volts. I went to the house and pulled the meter, still 5 volts.... This leads me to believe that the voltage is bleeding elsewhere....
 
benaround said:
bro, What happens when you disconnect 'all' the ground rods from the metal drinking bowl?

How did you turn off power to the heater, unit switch on heater or disconnect the cord

from the recpt?? Is there an EGC with the circuit conductors that supply power to the

heater?? Could the heater be defective and be 'leaking' this current??
Click to expand...
There were no ground rods on it originally. I started installing them to try and correct the problem... Thanks
 
bro15381 said:
I have went so far as to pull the meter socket at the house and I still have the 5 volts...
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Try lifting the neutral in the meter socket to isolate the PoCo feed completely (don't let it be connected to the grounding system). I sure would like to know what happens if you do that. If you can do it and let us know what happened, I will explain why later.
 
76nemo said:
Point taken, but do you all believe it???? Do you really think an induced voltage of 4-5V's will stray away livestock? I ask because I simply don't know, and would like to be informed. I don't see it regardless of the resistance to the animal.
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Yes it will. This is a well known and documented issue, typically from the utility neutral. Its grounded 5 times in a mile, the voltage drop of the neutral creates a parallel path to the earth.

The solution in Art 547 is to create an equipotential plane. See 547.10
 
Yes, the solution, 547.10, is to put an additional high wattage low ohm resistor in parallel with 5 other resistors of high value and the primary neutral. Now most of the current that was flowing on the rods is shunted to the equipotential plane. Done correctly the cow step potential should be reduced even though we now have more current under their feet. At least that is the way it is supposed to work. Not sure if it always does, but that is what we are required to do.
 
Sounds like the cause of the voltage is utility neutral current flowing onto your system. Mitigation options include a equipotential grid bonding the waterer to the spot where the horses stand, feeding the watering equipment with 240 V feed (if the equipment can be re-connected or may have to be replaced), or getting a Ronk Blocker installed to prevent the utiity neutral current from getting into your system neutral. This is installed typically near the service transformer.
 
'Stray current' issues are often related to current flow between the grounded conductor (neutral) and the grounding electrodes, either from the utility source or from improper neutral/ground bonding on the user side.

The thing that jumps out to me as strange in this case is that only one waterer has problems. If there is voltage between the GEC system and the soil surrounding the waterer, then why doesn't this show up at _all_ of the waterers?

Parts of the original description are also confusing. Is there voltage measured between the water itself and the tank that contains it, or between the water and the surrounding soil, or tank and surrounding soil? Have you attempted to measure _current_ flow between a water electrode or the tank and a soil electrode? Have you attempted to measure voltage or current between the problem tank and a non-problem tank?

-Jon
 
My thought is that there is something energizing the soil near one of the waterers, and that the waterer is properly at zero voltage relative to 'average' earth, but at 5V relative to 'local' earth. However the fact that this voltage difference remains even when the meter is pulled means that it isn't simply the circuit feeding the waterer or something else on the same service.

-Jon
 
Another thought, is there a telephone connection in the area ? or a cable tv connection ?

Can you get a non-metallic waterer in the mean time. Do you have any thing that is on a

battery back up or UPS system?
 
I have tried ti look for the explanation of a equipotential grid and just what exactly ot consists of, to no avail ???? the Code book refers to it several times but I cannot find out how to make one ???? Thanks, Scott
 
hardworkingstiff said:
Is there anything the utility company can/would do if this is the case?

Seems like 5-volts would indicate some higher than desired neutral connection in the system.
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There are many things that could be done, but I doubt the utility would sink any real money into a solution for 5 V. I think a bad primary neutral connection would cause higher than 5 volts to appear.

If the transformer is fed off a 3 phase feeder, maybe the feeder is unbalanced and high neutral current is causing the voltage to appear. That could be fixed relatively cheap.

If they are served from a single phase line, and the line is well loaded, there is not much that can be done cheaply. Now you are looking at upgrading the neutral.

Winnie's comment made me think that if the cause is not primary neutral current, because it is only showing up at one waterer, and pulling the meter does not cause it to go away, then maybe a neighbor has a 120 V or 240 V ground fault somewhere that is not being cleared by a breaker.

Bro - if you lift the utility neutral wire from your meter base and the voltage goes away, then it is primary neutral current causing the voltage. If it does not go away, then I think there is a secondary ground fault on a neighboring service.

Also, as a tip, pay attention to what is different about the waterer that has the voltage compared with the ones that do not. Look at things such as location, setup...

Do you have more than one metering point at your place?
 
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