I'm looking to add a 5 strand electric fence to protect my orchard trees from bears, not really worried about deer, but the bears will flat out DESTROY my trees in no time. The small part of my orchard (it's split in 2 by the driveway) is just under 1/4 acre but is SUPER rocky, so much so that I can't even put Tposts or rebar into the ground. I've been contemplating a few ideas of how to set up my e-fence & was thinking of concrete bases w/ the Tposts set in them but I've got a lot of logs up here & was thinking that I'd use some 22-26" dia. logs & cut them down to maybe 14-16" high, drill holes in them & hammer the Tposts in those holes (w/ the FEL) to hold it steady. Whatcha think? Any tips or ideas are greatly appreciated!
I had an interesting chat with young ranch hands from GrandPrairie Alberta at Laird hotsprings this past December concerning just that. Some of what they know is a bit conflicting with other research. What is important to know is the lowest should be no higher than 10 inches and the rest 3 more at 14 inches.
This is from young boys from a family farm of honeybees wintered in a barn and hives gathered around the outskirts of the barn when bears were not in hibernation. The bears were in close watch all the time. But the father had seen important things worth sharing here because bears were watched too.
Bears were seen flattening out under the wire to get through at even 12 inches. They don't care about the feel of current on the backsides. It is far more irritating to go over and get it through thier bellies. Therefore the lower 10 inch strand should be tightest of them all.
Another opinion I have about rocky country are memories of me trying to drive grounding rods that are 10 feet long down and they would stick. Rocky was also very poor at conducting current and required conducting ground wires encased in concrete such as in the footing of a house. Which concrete is considered superior and sometimes a building codes requirement.
If somehow you could hollow under the area of the uprights first of what Dubyaddy is talking about then fill it with standalone concrete at strategic points. Then with a 6-guage bare copper conductor buried along to interconnect all the posts to the neutral of the electric fence activation point, then you should achieve a loud shock and effective ground.
I am not an expert on electric fencing even though I am an electrician. But I think a good fence activator should have the ability to be automatic in the ability to turn on the strength of voltage output during dry spells and weaken it during wet weather. If it's that important you can also measure grounding by renting a ground conduction guage from an electrical contractor and it requires 3 points to make the test per directions.
I’m envisioning a hammer drill with a masonry bit boring into stable surface rocks enabling you to pound in expanding anchor bolts to attach surface mounted galvanized threaded female pipe base-plates capable of accepting threaded lengths of pipe to use with insulators as corner posts… 1 to 1.5 inch pipe, at least at the corners and as often as needed to enclose the area..
Thanks! Yep Rooney - was planning on my bottom wire at 8-9" high so I think that should solve the problem of bears crawling under. Another big ticket ? I have is should I run all 5 strands as hot wires or alternate hot & ground wires? From my research, alternating is best when you've got soil that doesn't ground well but then they have to touch 2 adjacent wires to get shocked. Guess I could run multiple grounding rods but I'm leaning towards all 5 wires as hot. But not 100% sure if that's the right thing to do...
An all hot wire system's only drawback is when put to use on a rocky terrain. Your rocky. Meaning your problem is getting a good path for current to flow to the collection point of the high voltage. There is only one option for such an all hot wire system is to assure the flooring that the bears stand on are adequately connected to the collector point (or point of common ground in electricians jargon).
The simplest way to accomlish -is at least a 4 foot wide layer of chicken wire stretched along flat and under the 8-9 inch lowest wire. That's what I would do. As long as you can make one continuous run of the flat wire then that's what's going to be collecting bears feet back to the common connection point.
I have never done an electric fence but I think that is a better one for an all above hot wired system. There are no issues in rocky ground when matting can be connected all around in one flat roll.
Were the distance to be enourmously too much for a manufacturer to produce such lengths of chicken wire, then in which case, I would still create a way to make connectivity. Such as thicker wire and welding or clamping with copper crimps.
No ground rods needed, unless by electrical code. A rod of 10 feet in length may still be required for safety making connections and/or as required by your County, State, National requirements of code because of the primary 120 volt feed, which is other safety, but that's kind of a take away from the method outlined.
Sorry for all the repetitive words but when all you have done is wires and electronic design your entire life and are used to working by yourself it becomes hard to convert what I see as clear as day into anything very brief.
coolbrze said
...should I run all 5 strands as hot wires or alternate hot & ground wires? From my research, alternating is best when you've got soil that doesn't ground well but then they have to touch 2 adjacent wires to get shocked.
An interesting point of view that comes from those that have engineered the NEC (the codes), and I had learned this from many years of great instructors with high level of knowledge and even if this has nothing to do with fences, is that milk cows stop producing milk when ground currents trickle from leg to leg.
It's hard to guess if the bother for the cows is in the belly or feelings in the feet. Which means my previous guess that bears don't like getting zapped in the belly could be a false one. Then if bears are anything like milk cows it could be that neither can stand being stunned through the feet.
Which is part of the reason I brought up the flat underneath wire idea.
Yes I had also read about the chicken wire around the bottom if I go all hot wires. One question... how close does the ground rod need to be to the energizer? I heard I can run multiple grounding rods but I'm not sure how close they need to be to the energizer or the fence itself. there is some "not so rocky ground" about 20' away that I can definitely drive a few rods into but not much decent ground any closer...
There are safety issues everywhere when it comes to grounding and where connections get made based on rural farming operations verses near a home etc. Which means there's no way of getting around asking the question to a qualified company with the proper license etc. It makes more sense to ask if anybody knows a phone number of anybody with electric fence installs with the specific licensing for whatever state you live.
There are battery powered and solar rechargeable fencers available at Tractor Supply. You can place the fencer anywhere along your string . The fencer needs to be grounded to build up the charge in the fence wire. What is happening is the fencer acts to create a capacitance charge by building a 2000 volt potential between the fence wire and earth, it pumps electrons from one to the other and when the animal touches the wire and earth - zap - capacitor discharged. You can locate your battery powered unit where you can most easily pound in your ground rods. These units are made to be used in remote pastures where no electricity is available. Use a deep cycle/marine battery. The user manuals are available on the Tractor Supply website and give good explanation for setup. One thing mentioned in the manual is do not charge barbed wire, only smooth wire, one does not want to get clothes tangled in a charged barbed wire you cannot untangle from.
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