“Over-Engineered” and “Under-Powered” Electric Fences

Over the years, I have had opportunity to work with and visit with many New Zealanders here in the US. I don’t think that it is any secret that many of them have grown up with hi-tensile electric fencing and in general they are 20 years ahead of us with technology and practical use.

Two comments that I have heard repeatedly is that they accuse us Americans of “over-engineering” or over-building our fences; then also that we “under-power” them. In essence that is saying we spend too much money on building the fence and too little on the fence charger.

I would tend to agree with them on that as I have seen many people that make both of those mistakes when designing and installing their first grazing system of hi-tensile electric fencing.

One of the key benefits of using high-tensile wire is that it allows for greater line post spacing than conventional wire; usually 50 feet as a minimum. Also, many people will over-tighten the wires. You want a flexible system that allows for wildlife impacts, snow and ice loading, general equipment impacts, etc. Over-building a hi-tensile electric fence makes it too rigid, and you lose this benefit. Plus, it quite simply, costs you more for materials to build it.

Many of us in the US grew up with 5 strand barbed wire fences. We were taught that rigid and tight was the way to build this fence and it was. Ten to twelve foot spacings on line posts was pretty standard….so, when you tell someone with that mentality, that they should go fifty feet or more – they sometimes kind of stiffen up on you.

I once saw a wild turkey glide into a hi-tensile fence wire. That’s equivalent to a very large bowling ball flying through the air at 40 miles per hour. The fence was unscathed as the turkey walked around, with a few less feathers, wondering WTH……a conventional rigid fence would probably have needed some repairs and tightening.

Anyway, stretch out your line post spacings, and allow your hi-tensile wire to be flexible. Using a line post such as the PasturePro Post also contributes to allowing the overall system to be flexible and forgiving.

There are several other articles on this blog about fence chargers and selecting the right size, so I won’t rant on about the energizer. Just remember to NOT skimp on the charger.  Don’t over-build the fence and don’t under-power it, either.


About Gary Duncan

Gary has been active in the fence business for over 15 years. He also raises Highland cattle in a management intensive grazing system and was the first person to market the PasturePro post back in 2005. He enjoys discussing all things grazing and is the main contributor to the blog.
This entry was posted in Buying Tips, Fencing Tips, Installation, Ruminations. Bookmark the permalink.

8 Responses to “Over-Engineered” and “Under-Powered” Electric Fences

  1. avatar Ryan says:

    While I don’t doubt that 50 foot spacings and less tension works well for cattle in North America and sheep and cattle in NZ with their lack of sheep predators, but I do not think it works for sheep in NA. Coyotes are too smart and creative and for an HT fence to work on them it needs to be tight and supported by closer post spacing. Maybe not 10 to 12 feet, but 20 would be the max I would use. If the wires are not tight and supported, they will not press through the coyotes hair to the skin and provide the shock required to make him think twice.

  2. avatar Steve says:

    Ryan, how many wires and how closely spaced are the wires in your sheep fencing? At 20 foot post spacings do you eliminate most of the low spots where a coyote or dog could slip through? Do you run all hot wires or do you alternate hot/cold?


    • avatar Ryan says:

      My HT fences exist in several formats. I have tried several, but the one I am most pleased with is 9 wires. 8 wires spaced 6 inches apart, with the ninth wire offset 18 inches on the outside of the fence about 15 inches from the ground. Bottom wire is hot the wires then alternate hot and grounded. The offset is hot. 20 foot post spacings provides excellent coverage of low spots. I do double H braces at all corners and ends and stretch the wire tight. The combo of tight wire and tight post spacing makes it difficult to even crawl between the wires.

      • avatar Steve says:

        Wow, now that sounds like a fence to see. With your double H braces I bet you can keep the wire fiddle string tight. With the bottom wire hot do you have difficulty keeping the voltage up?

        I spoke this weekend with a cattle/goat producer in Tennessee who uses 2′ woven wire on the bottom of his fences and then stretches hi-tensile electrified wire above it. He said that after watching goats, dogs and coyotes encountering fences he decided they rarely will jump over the fence and the woven wire keeps them from crawling through. It’s a large acreage and he can’t keep the voltage up high enough when it’s electrified close to the ground so he came up with the woven wire/ht electrified wire as a solution. He uses guard dogs and I believe this style of fence keeps them in, but you do wonder if it would keep coyotes out.

        I liked the idea of a 2′ woven wire, as it would be much less expensive to buy and much easier to roll out and stretch and would still provide the crawl through resistance you want from your woven wire.

  3. avatar Ryan says:

    I spray under the wire with round up. I use to try and let the energizer burn through, but it made me anxious fearing that it would rain and drain all the power out of it. I have also used kencoves 7-24-36 page wire with HT wires above it and energized the page wire and all. I have yet to see anything get through that fence.

    • avatar Steve says:

      We’ve used the same HT woven wire as you and really liked it. Easier to install and less costly than standard woven wire. Looks good as well. We used Gripples to join the rolls of wire and found they allowed us to fine tune the tension when stretching the woven wire. We can vary the tension of the top and bottom wires over rises and through valleys with the Gripples, avoiding the difficulty of uneven stretching that can occur with woven wire in those areas.

  4. avatar Gerell says:

    Wow! you guys are discussing the same issues we face here, with preditors….mostly dogs and coyotes…. but we also have to negoiate fairly steep hills, water ways and still keep the sheep in and safe.
    We are trying to find good solutions to going over hills and through some steep low places and realize that putting in wood line posts in these areas will help, but is there something else we can do to make it better.
    I guess I fit in that over build it catagory… rather have it and not need it as to wish I had done better.
    It seems tho that putting the woven wire up under HT is kinda defeating the idea of HT…???

    • avatar Gary Duncan says:

      Hi Gerell — Although I love the versatility and economy of 12.5 gauge High Tensile smooth wire – there can be times where HT woven wire can be a benefit. Those times would include predator control.
      Actually HT woven wire is fairly new in North America. I’m talking about 12.5 gauge with fixed knot rather than a hinge knot at the wire junctions. The 7-36-24 HT woven wire mention above will also adhere to steep slopes and terrain changes quite well.
      Cost is always a factor. 12.5 ga HT smooth wire is around 2-1/2 cents per foot, so 7 strands of it will cost around 18 cents per foot. Whereas the above mentioned 7-36-24 woven wire will cost around 30 cents per foot. Not quite double but close. The prime benefit of the woven is that it has a vertical stay every 24″, which maintains a consistent vertical wire spacing.
      With steep and rough terrain you will likely be destined to reduce your post spacings so that the wire can follow all the dips and bumps of the terrain, in order to keep predators out.
      As Ryan mentioned above, to keep the grass load down you may have to spray your fencelines, along with using a large size charger if you want to energize the woven wire. The stand off or ‘trip wire’ mentioned above also works well.
      As far as defeating the purpose….I dont know that ‘this’ is true. You still have the 7 strands of HT wire, with the woven you just have the addition of the vertical stays every 24 inches. It still has the great characteristics of HT wire. It is springy & bouncy & extremely strong.
      Hope this helps. Out of curosity, what area of the country do you live ?

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