Electric fence problem

[gberry]

We separated our cows and calves yesterday. In the past we have tried to wean with a single hot wire between, but always have 3 or 4 calves that go over or under the fence. These often become fence jumpers so for the last 2 years, we have separated them with 3 hot wires. This has worked well, but dry conditions have made it hard to get a good ground this year. To make a long story short, seven calves went through or over the fence last night. I decided to add another wire on top and a ground wire. This is where my question starts.

A portion of our weaning pen is 4 strands barbed wire on T posts. I decided to attach the ground wire to a strand of barbed wire and later noticed that if I touched this strand and the next wire up, I would get shocked. I tested the fence and found that the ground wire actually had about 500 volts on it. The hot wires are not touching the ground wire or the barbed wire. Can anyone explain how this wire is getting 500 volts on it? The ground wire is at least 8 inches from the hot wires. Do you think a few weeds could conduct this much current? Is there a problem with my ground?

 

[dcara]

There could be a couple of different things hapening depending on the specifiics of the installation and measurement. 1st, Is the ground wire that you have tied to a barb strand also tied to a deep ground rod back at the charger? If not then you need to tie to a deep ground rod at the charger. Also note that the combination of shallow Tposts and poor connection from the barbwire to the Tpost make for poor grounding. You could aalso tie the ground wire to a deep ground rod along the fence every so often, and by deep I mean at least 5 feet in dry conditions. 2nd, between what 2 points did you make your measurement of 500V (the 2 wires mentioned or was it one of the wires and ground/dirt)? 3rd, Yes. Weeds can conduct current from the hot wire to the ground wire, especially if covered with morning dew. Again this could be helped with deep ground rods tied to the ground wire along the length of the fence.

Regarding calves and electric fences, I have seen them jump thru a 2 wire fence with no apparent notice of it. I have a couple theories here. One is that when they jump thru, both feet are off the ground when they actually make contact with the wire and so they do not get a shock. Another is that if its a pulse type charger then even if their front or back feet are on the ground at the begining or end of a jump and they do make contact with the fence then there is still a very good chance there will not be a charge pulse on the fence at that instant.

 

[cfpinz]

How many joules does your charger have and how many ground rods?

Also, if a cow/calf gets shocked behind their eyeballs sometimes it will cause them to jump forward instead of backwards. They percieve the pain coming from the rear.

cfpinz

 

[donnaIL]

buy the best charger you can afford...ground it with a 5 or 6 foot grounding rod.. drilled in to the ground, your hot wire will be grounded and yes the will get "shocked".

This post kinda reminds me of birds sitting on live electric wires...they are not grounded:) donna

 

[gberry]

The charger is grounded. We have 4 ground rods 8 foot deep and 10 feet apart. The charger is also plenty strong reading over 8000 volts on the fence in question.

The barbed wire that I am talking about is not connected to the grounding system for the charger. We simply set 2 more wires about 8 inches inside of our existing fence. One of these was placed higher to give a visual deterrent to fence jumping. The second is not charged and is connected to a strand of barbed wire which is attached to T posts. This way when the calves push into the fence, we will have a more sure ground than their hooves on dry dirt. When I ground the fence tester to the ground wire the hot wires read about 9000 volts. They read the same when grounded to the dirt.

When I ground to the dirt, there is 500 volts on the ground wire. Why is this?

 

[hillrancher]

In dry times I run a ground wire tied directly to the post in the center and a hot on top and one on the bottom. Then if the animal touches the top and center this is a circuit or the bottom and center this is a circuit or both and center. Ground the center wire at charger with the ground rod and ground on the charger. The ground does not need to be moist to work.

 

[gberry]

I guess to simplify my question, how can 500 volts be present on a wire that is not connected to the charger and is not touching (or within 8 inches of) any of the hot wires?

 

[hillrancher]

I guess to simplify my question, how can 500 volts be present on a wire that is not connected to the charger and is not touching (or within 8 inches of) any of the hot wires?

It is within the electric field of the hot wire same voltage with lower amgerage.

 

[Susie David]

We use the whole wire fence as a ground along with the ground rods.
Voltage will be present...amperage isn't there.
Our barn reads a few hundred volts with the meter but won't shock anyone.
Basically....voltage is the number of electrons flowing in a conductor....amperage is the strength of the flow....Joules is a measure of shocking strength.
Just my two bits worth....asked for or not. Dmc

 

[cfpinz]

My first thought is a faulty insulator. One that looks good but has broken down and allows some voltage creep.

cfpinz

 

[cowlady1]

pour water on your ground wire to see if it makes a difference.I do this in dry weather & it makes a better charge. Is any of your wires touching your posts anywhere? I've had deer pull the wires into the posts and made me problems. Your calves could have done this. You can take your charger to get checked to see if it's working proper.I do know in dry weather if you pour that water on ground posts your fencer will make a difference.

 

[cowlady1]

I just noticed you have your ground wire on barb wire attached to t-posts.Get a ground post and attach your wire . Your t-posts ground but the way your hooked up your making a short. sending your current through your wires to posts. Calves are not getting shocked. Hot wires are not hot enough for them & dry weather isn't helping. Pour water on ground post after you change your ground wire. You should see a difference.

 

[dun]

Normaloly it's an inadequate gorunding system. In exceptionally dry soil you sometimes need as many as 8 or 9 ground rods.
http://gallagherusa.com/ has a fencing manual on their website. It has a simple test for the grounding system.
Next most common cause is an accidental short somewhre, bad insulator or a wire contacting a metal post somewhere. Next would have to do with the electrical properties of lines of flux cutting other lines of flux and basicaly creating a generator of sort.
With a direction fault finding fence tester it's pretty easy to rule out the first 2. The easiest and usually best method is to test the ground system and add more rods as needed.

 

[grannysoo]

In dry times I run a ground wire tied directly to the post in the center and a hot on top and one on the bottom. Then if the animal touches the top and center this is a circuit or the bottom and center this is a circuit or both and center. Ground the center wire at charger with the ground rod and ground on the charger. The ground does not need to be moist to work.

This solved my problem too. With the drought we had this spring, my fence would not work at all. Had grounded with a 12' copper ground that was plenty wet. Nothing worked until I took one of the fence wires off hot and made it a ground. Doesn't matter how dry it is now. This works!

As to your question of the voltage in the ground, you've got something hot bleeding into it somewhere...

 

[KenB]

The charger is grounded. We have 4 ground rods 8 foot deep and 10 feet apart. The charger is also plenty strong reading over 8000 volts on the fence in question.

The barbed wire that I am talking about is not connected to the grounding system for the charger. We simply set 2 more wires about 8 inches inside of our existing fence. One of these was placed higher to give a visual deterrent to fence jumping. The second is not charged and is connected to a strand of barbed wire which is attached to T posts. This way when the calves push into the fence, we will have a more sure ground than their hooves on dry dirt. When I ground the fence tester to the ground wire the hot wires read about 9000 volts. They read the same when grounded to the dirt.
When I ground to the dirt, there is 500 volts on the ground wire.
Why is this?

It could be caused by induction, or something touching between the hot wire and the barbed wire.
The best way to remedy this is tie the electric fence ground to the barbed wire. This will bleed off any stray voltage.

 

[Earl Thigpen]

I think KenB is getting pretty close to the root cause.

You have charged wires running in parallel with your barbed wire, right? How much distance do the charged and uncharged wires run? It's possible that you are getting some inductive coupling from the charged wires into the uncharged barbed wires. Same principal as how a transformer works.

To cure the problem you will have to make absolutely sure the barbed wires are grounded. You may even have to drive ground rods (6' deep) at every second or third "T" post and connect the barbed wire to the ground rods through a very good electrical connection.

Or don't worry about it. Once the little darlins get whacked once they'll steer clear of the fence.

 

[gberry]

I appreciate all the responses although I still don't think I understand the voltage on my ground wire. Perhaps it is induction although the wires are at least 8 inches apart at all points.

The fence is working fine with readings of about 8-9000 volts on all the hot wires. I'm sure we'll be able to keep the calves separated. We always have before. I was just looking for ideas as to the voltage on my ground wire.

I will look at the gallagher website because I think it may be a problem with my ground for the charger. I was hoping someone on here had a similar experience, but I can tell from a lot of the answers that my question is not worded very well.

Thanks again.

 

[Earl Thigpen]

I appreciate all the responses although I still don't think I understand the voltage on my ground wire. Perhaps it is induction although the wires are at least 8 inches apart at all points.

The fence is working fine with readings of about 8-9000 volts on all the hot wires. I'm sure we'll be able to keep the calves separated. We always have before. I was just looking for ideas as to the voltage on my ground wire.

I will look at the gallagher website because I think it may be a problem with my ground for the charger. I was hoping someone on here had a similar experience, but I can tell from a lot of the answers that my question is not worded very well.

Thanks again.

Mr. Berry, I just told you why you are getting power on your ground wire - through inductive coupling. The voltage is being INDUCED to the parallel ground wire because it is not well grounded.

 

[KenB]

I appreciate all the responses although I still don't think I understand the voltage on my ground wire. Perhaps it is induction although the wires are at least 8 inches apart at all points.

The fence is working fine with readings of about 8-9000 volts on all the hot wires. I'm sure we'll be able to keep the calves separated. We always have before. I was just looking for ideas as to the voltage on my ground wire.

I will look at the gallagher website because I think it may be a problem with my ground for the charger. I was hoping someone on here had a similar experience, but I can tell from a lot of the answers that my question is not worded very well.

Thanks again.

If you will read back through all of the replys most of them answer your question. Now it is up to you to accept them.
If and when you find the problem, I'll bet it has been answered here.

 

[gberry]

Thanks again. I agree it is induction that is causing the voltage. I just wasn't familiar with that phenomenon. I wasn't trying to be rude, I just thought I hadn't expressed my question clearly as a lot of the folks answering seemed to think my hot wires weren't functioning properly. The link at gallagher explained it clearly as did Mr. Thigpen and Kenb as well as several others. Thanks again.