Electric fencing for dummies

It may be possible to get a few more years out of a less than ideal fence by adding a hotwire. Photo by Hannah Reding

There are a lot of things that look complicated but one does not dare to ask others about, since one is supposed to know. Electric fencing is one of those things.

Why would you use electric fencing? Traditionally, animals that you have in the paddock like to rub on fences which can do an awful lot of damage to the fences as well as to animals, especially if the present fence has barbed wire on top. If you electrify your fences you keep your animals away from posts and wires and prolong the lifetime of them.

At the same time, you put up a barrier which animals soon learn to respect. In other words, electric fencing not only keeps your animals within the boundaries they are supposed to be, but it also protects your fences from damage.

Electric fencing is also the answer for areas where temporary fences are required, i.e. shelterbelts, strip grazing, dam protection etc.

How does it work? The principle is quite simple. Just imagine a broken circle. When you close it, you get “snapped”.

In effect, you attach the positive terminal of your energizer (+) with an insulated lead to the fence you want hot. Then attach the negative terminal (-) which is on the other side of the broken circle to the earth. The earth may consist of one, two, three or more galvanised pipes or rods that are about 6 ft long, at least 3 metres apart and have been hammered into the ground in a straight line in a permanently damp area, the wetter the better.

Caution: If you’re not familiar working with electric fences, consult your electrician. This information is intended to provide general tips — please contact your electrician if the problem persists or you need further advice.

Over 90% of all failures can be traced back to poor grounding. If an animal stands on the ground and touches the hot wire it closes the circuit and gets “snapped”. However, a bird that is sitting on the hot wire does not feel anything because it does not close the circle.


All wires you want “hot” must be properly insulated. That means the hot wire must not be in contact with the ground through battens, posts, waratahs or for that matter any uprights.

All wires you want "hot" must be properly insulated.
All wires you want “hot” must be properly insulated. Image by Manfred Richter

This would close the circle and “short the fence out”. When it rains wood posts or battens get soggy and become conductive. Waratahs are conductive all the time.

Therefore, plastic insulators are used to keep the hot wire away from any possible contact with the ground.


How Do I Go About It?

There are two possibilities:

  • You can electrify an existing fence by adding one or several permanent hot wires, or
  • You can add hot wires when you put up a new fence.

In both cases, you save a considerable amount of money. A permanent fence may no longer be strong enough to keep the animals within the boundaries. However, an electric wire or two will keep them away — especially if you use outrigger insulators — and take off the pressure on the old fence. It will last for another few years or even longer.

If you put up a new fence you can use posts every 6 to 8 meters; no battens are required. Strain the wires about half as tight as you would normally.

Three to four hot wires are recommended for cattle, five to six for sheep. In case they get cunning and jump through the fence — which would not close the circle and, therefore, would not “snap” them — you have to resort to a system that has alternate “live” and earth wires. In other words the top, middle and bottom wires are hot, the second and fourth are neutral. If an animal touches both wires it closes the circle as well. This system is a bit hard on dogs because they have to jump over the fence and can no longer go through them. It is also an excellent system in case earthing your unit is difficult because the soil is too dry.

Remember: If you are buying a new computer or modem, talk to your retailer about a model that will work satisfactorily from your premises.

Image by Markus Distelrath from Pixabay

There are basically two types of energizers:

  • Mains powered units which are plugged into a 240 V socket. They are certainly more economical than the next class of energizers.
  • Battery-powered units are driven by either batteries that are periodically replaced or by a car or marine battery. However, they have to be charged which can be done in two different ways:
    • With a battery charger which means you require two batteries (one to be charged and the other one “working”).
    • With a solar panel that continuously charges the battery during daylight.
File image by Kate Cox
Five-Step Electric Fence Check
The ideal way to set up your electric fence is to feed the power out from the energizer in a "star" fashion, with no closed loops and low currents in parts of the fence that closely parallel phone lines.
The ideal way to set up your electric fence is to feed the power out from the energizer in a “star” fashion, with no closed loops and low currents in parts of the fence that closely parallel phone lines.

1. Find out where there are telecommunication cables or phone lines on or near your electric fence. This includes both buried and overhead wires and cables. They almost always run along or near the roadside reserve or along driveways. A marker post or grey connection pillar should be nearby. If you can’t work out where they are, call Telecom on 124 for help.

2. Identify the electric fence wires and connecting leads within 100 meters of the phone lines and running either parallel or nearly parallel to them. Long sections running parallel to the phone lines feeding other sections are more likely to be a problem than short sections that go nowhere else.

Avoid doing it this way.
Avoid doing it this way.

3. Check the current in these wires. You can use a Red Snap’r Fence Doctor, Pakton Power Probe or any other fault finder to do this. The current in a well-maintained fence should be less than two amps per kilometre of energised fence line. If it’s higher, there could be a short on the fence, too much overgrowth, live wires contacting the ground or old deteriorating insulators. Work along the section with high current, and the downstream parts fed via this section, to locate and fix shorts by removing overgrowth, fixing live wires touching the ground and replacing old insulators.

4. If, after fixing faults, the current is still too high, find a way to feed the main supply through sections of the fence that are further away from the phone line. For example feed the power out through fences in the middle of the farm, away from the phone line, rather than through the roadside boundary fence next to the phone lines.

5. Check that the earthing system meets the manufacturer’s instructions. Make sure that it is at least ten metres from any buildings and ten metres from another earthing system. Also check that the energizer, earth electrode connecting lead and output leads to the fence are well clear of phone lines.

© 2004 Hans Dresel, of Artex International; the home of Red Snap’r electric fence systems. Artex achieved the accreditation of ISO 9002 in 1995 and in 2001 qualified for ISO 9001. artexnz@xtra.co.nz.

19 thoughts on “Electric fencing for dummies

  • January 14, 2013 at 2:46 pm

    Haha, please publsh an article on electric fencing for HORSE dummies!!

    • August 24, 2020 at 7:56 am

      I want to spray rubberized coating around my front bumper then put electric fence wire around it for rioter

  • July 2, 2014 at 3:23 pm

    I bought my electric fence supplies from one supplier except for ground rods and T Posts. I installed per instructions. I have arcing from the fence wires to the T Posts. This is mostly random arcing, one then another. The fence charger is Stafix X3 and I measure 9.9 KV, but that is the maximum my meter will measure; therefore, it could be higher than 10 KV. The supplier says it is no problem having arcing. Tru-Test, the manufacturer of the fence charger says arcing is not a good idea and I should replace the insulators. What do you say?

  • October 29, 2015 at 10:19 am

    Im going to put one hot wire on about 400 feet of corral panels to keep my Mule from eating my neighbors Horses tails. I have found some pretty good looking plastic insulators that would only keep the wire about 1/2″ away from the panels.
    Do you think that is to close? In the past I have modified 5″ Tee post insulators and they work great but don’t last to long. Im just worried that even if wire is not touching metal that it could jump and make contact when wet.
    Thanks a bunch. Jeff

  • May 12, 2016 at 9:06 am

    This is a great article. We have found that people often overlook a few basic steps to ensure that they set up their electric fences safely. Wish more people would have a hunt around for these types of articles before giving it a go for the first time!

  • August 10, 2016 at 10:19 am

    A question:
    I have a 60 km electric fence system. In many places there is the opportunity to make the circuit circular – that is, to connect the beginning of an elect fence wire to the end of the same line.
    The question is – is it better (in the sense that the system works better) to complete this loop or is it better to not join the end to the beginning?
    Also, where you have two or more hot wires on the same fence line, should these be looped back to each other or do they work better if they are individually hot?

  • August 31, 2016 at 4:51 am

    what sort of fence charger does poly wire need. I have a very amall area, araound 200 feet

  • March 20, 2018 at 6:22 pm

    This is a great article. We have found that people often overlook a few basic steps to ensure that they set up their electric fences safely. Good thing you have shared this information with us!

  • October 13, 2018 at 3:04 am

    Is it necessary to use wooden posts? I am looking to split a pasture and would like to have the option for portable fencing.

  • December 4, 2018 at 5:29 pm

    I installed a 100 mile fence charger on a one acre fence only break in fence is the gate I have a ground rod at the end of it hooked to fence were there is no hot wire.i have only one hot wire running 6 inches from the bottom of the fence .I have 2 5 foot rebar ground rods about 5 feet from charger and two 3 foot about 6 feet from them yet no shock anywhere

  • February 26, 2019 at 12:56 am

    I have a cable reel which has become tangled. Does anyone have any suggestions on how to disentangle and rewind onto the spool!

  • May 2, 2019 at 12:55 am

    I have a question please. The farm I have my horse stabled has already electrified all their fields using mains supply. A number of us share the field, all with different needs, example some horse need grass some not so much. I have made an area using the existing supply by placing posts and using rope. I used a gate handle at one end and connected the metal hook onto the existing hot wire fence. The other end I tied round a wooden post that I insulated with a plastic bag. It works fine. The problem is however someone else from the yard has also done the same thing using their rope and posts but they have attached the wire metal hook on both ends. My question is would the electricity not get shorted if both ends are supplying the same wire ?

  • September 9, 2019 at 5:11 am

    Question: Can I wrap insulation around my charger? The ticking is annoying nearby tenants.
    Is it necessary to have airflow around the charger; ie. I could make a box around it if needed. The charger is not warm so does it matter if insulation is right on charger?

  • October 29, 2019 at 12:38 pm

    I have 4 strands of high tensile wire with barb wire between each. Why is my barb wire hot and it nailed to wood post not touching anything

  • October 29, 2019 at 4:31 pm

    It MUST be / HAS to be touching somewhere – that’s why it’s hot! It’s amazing how difficult it is sometimes to spot that bit of wire/nail/metal/wet grass etc., which must be touching your system…the barb is hot because of that hidden short then it is acting as an hot wire because it is effectively insulated because it’s nailed onto the (insulating) wood. Maybe even two nails touching, inside the post? Best have a closer look, or better still, buy one of those little devices which show in an instant where the contact is. They are expensive but more more than well worth it in the long run. Good luck. GH.

  • May 25, 2021 at 7:26 am

    what was your response to this question?


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