There are two different types of high tensile fences on my place. The original fence was built to hold and protect sheep so it is a five strand high tensile that reaches down to about 5 inches above the ground. The new fencing, which was installed in 2017 and was built for beef cattle, is only three strands and terminates about two feet off the ground.
The original fence is a nightmare to weed whack under during the summer months to keep the fence as hot as possible so I ended up moving all the bottom insulators up as high as they would go so I can get the weed whacker under the bottom line and keep it clean. Like I said, that fence is a real pain.
Now all of this fencing is powered by a 26 Joule 120V energizer. This baby really pulses, and if the fence is clean, it will sustain about 8,000 volts across the entire system. By mid-June, the juice starts to leak out due to the wet green forage growing along it, and the fences max out at about 3,000 volts. This is by no means suitable for training cattle, or any other animals for that matter, so I was lugging the portable solar charger around for a few weeks just to make sure the interior fencing was well recognized and respected by the new tenants this year.
So, I was happy that the cattle were all staying behind the fences lately despite the low voltage. This weekend I learned why that is.
On the five strand original fence, all the lines are charged all the time.
On the newer three line fence that we built, the charged lines are staggered so the top line is hot, the middle line is connected directly to the ground, and the bottom line is also charged (hot). This is called a Pos/Neg fence.
I had heard in the past that despite the lower readings on the fence, the fact that the subject was immediately grounded upon contact would make the zap a lot “hotter.” I am here to today to confirm that this notion is true.
I forgot to turn off the fence Saturday morning and while walking back from checking the cattle I decided to climb though the fence to move something really quickly. My hand was around the ground wire when the back of my neck contacted the high line on the fence.
A pure blue ball of pain engulfed my vision. I involuntarily screamed. It felt like there was lava shooting out of the back of my head, out the soles of my feet, and up my spine. I was still very conscious despite the pain and immediately thought in my head, “I have got to get off this fence” and threw my body to the ground. I was safe, but boy was my head scrambled. I checked to see if I was actually smoking, and finding no evidence of having been cooked, I moved on with my day.
That shock was many magnitudes worse than the other fence. Having the ground immediately available for the voltage to move through my body made a huge difference in the delivery of the training stimulus. In other words, it really hurt.
So, I can now report that two things have been confirmed. Building a fence with a ground wire in the middle is a great way to deter animals from leaving your property and one would also assume it deters predators in the same way. How can this help you? Well if your fence isn’t holding charge the way you’d like due to lack of soil moisture, this is the way that I would recommend you design it.
Here’s a quick video to show how to set up a Pos/Neg fence if you’re using electric netting. It also describes some issues to beware of when running a Pos/Neg fence set up.
I am not any of the above, so maybe that discredits me, but here is an idea on how keeping the ground rods in damp soil would cause a better bite when an animal hits the fence. First of all on a pos/neg fence, if the fence is not connect to the ground wire on the fence, to the ground post on the charger you’re right, theoretically the circuit to be completed back to the ground rods would need to travel all the way through the ground, but that isn’t exactly how I understand it. The key for what your are talking about, “having your ground rods in damp soil” is that for it to work one will need to connect the ground wires in the fence to the ground post on the charger and the negative post is also connected to the ground rod field. (shown in the pos/neg diagram in the article) so in this case the ground wires are directly grounded to the ground rods in the damp soil, and when an animal touches both the positive and negative wires in your fence, wow, look out!! Hope this makes sense. I do live in the west, and that is how I build my fences.
I would have added this to my other comment if I would have read your introductory article first.
Yes, you’re right. We’re on the same page, but perhaps I didn’t explain it as well. A regular all positive fence requires the charge to travel through the soil to the ground rod and back to complete the circuit. Perhaps Pos/Neg is the wrong label. Basically, having a positive wire and a negative/ground wire attached to the ground rod means that, as you said, when the animal touches both they instantly complete the circuit and they get a big shock.
Thanks for writing in and helping clarify this!!
I make my bottom wire if it is under 12″ in height a positive, with the option to make it negative with a double throw cutout switch. you may need a few switches if you get tired of burying another wire for just the bottom wire under gates etc. But it has worked for me! I flood irrigate and at times my bottom wire is submerged, or later in the season tall grass is on it. But I need it hot in the spring, just remember to turn it off and sequence your switches.
Stihl makes a trimmer called a power scythe. It works great to trim under our 6 wire hot/ground fence. I do turn the fence off while I am working under it, and tie the lowest wire (ground) up with a couple of pieces of baling twine. The twine gives me about 6″ of working space, enough to get the cutter head in and not cut the wire. No spinning lines wrapping themselves around anything they come in contact with. The scythe actually looks like a small section of sickle bar on a stick. You can change the angle of the head to the stick; really handy when I need to cut across a ditch to clear the bank on the other side.
One caution on using a Pos/Neg fence in a high vegetation environment. Lush green vegetation in contact with both a Pos and Neg wire is a “short” in the fence. These vegetation shorts can have a greater effect on your fence than do vegetation shorts thru the dirt. This is due to the Pos/Neg fence having a more conductive ground system. Often times in a high vegetation/moisture environment utilize large energizers (50 joule or larger) and at least 10, 6′ galvanized ground rods (more may be needed) make sure your energizer lead-out wire is 20 ohms resistance or less. When buying an energizer pay no attention to the distance ratings buy the biggest energizer you can. More joules will do 2 things, push a charge a greater distance but often more importantly it will overcome more vegetation or “shorting on the fence. After installing, servicing and selling electric fence for 25 years I have never had anyone tell me my fence is to hot. More power is always better.
I almost never see any mention of how time consuming and tedious it is to keep electric fence lines mowed so glad to see it mentioned in your article. I certainly wasn’t aware of how much time I would need to spend mowing under my electronet( for sheep) so that count on it working effectively. This is a huge draw back to electronet, as I see it, or perhaps to any electric fence that can contain and protect sheep. I’m loking forward to the day when my perimeter fence will be woven wire which may look messy when grass grows under it but will still do it’s job.
thanks for your comment!
Yes it is a pain and I have tried lots of different ways and the way I do it now is…I leave it be! Every year i pick one 200 yard area of fence and clean all the perennial plants off the fence during the winter. Then come summer i let the annuals do their thing. Yes I lose juice, but if the cattle have enough grass and water they will USUALLY stay put…anyway the netting is really tough to deal with so i wish you luck and keep up the good work!
My big problem with mowing under fences is I have thick, stalky weeds, and I nearly always have an irrigation pipe there.. that makes the nylon string useless, and it’s far too dangerous to go there with a metal blade.
I’m looking for a long pole hedge trimmer, I think that would make very quick work of any weeds and would be forgiving if I hit my aluminum pipe
I also have pipe that runs under and along my fence line…honestly I use a bladed brush cutter and I’m just really careful around the pipe. I have cut it multiple times but i keep a fence fixing bag with me with all the stuff i need to fix it after i mess it up…BUT i still have to drain the line to relieve the pressure so i have become extra careful under those fences!
If the fence is permanent you can apply ground killer right under the fence. Be very careful with the ground killer, one drop goes a long way. I would spray the least amount you can spray around the perimeter and wait a few days to take effect, normally 3 days. Then you can go back and address missing areas if required.
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