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There are a lot
of things that look complicated but one does not dare to ask others
since one is supposed to know…!!!. You know the feeling! Electric
fencing is one of them.
Why would I use electric fencing? By nature,
animals that you have on 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 does not only keep your
animals within the boundaries they are supposed to be, it also protects
your fences from damages. 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
other words 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 approx. 6 ft long, at least 3 metres apart and have
been hammered into the ground in a straight line. The best earthing is achieved in a permanently damp
area, the wetter the better.
Over
90% of all failures of an electric fencing system 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.
Insulators
All
wires you want “hot” must be properly insulated. In other
words the hot wire must not be in contact with the ground through battens,
posts, waratahs or for that matter any uprights. 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 times.
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 no pressure is anymore 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 – 8 meters; no battens are required. Strain the wires about
half as tight as you would normally do. 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. 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 due to too
dry soil.
Types of Energizers
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 marine battery ( Deep Cycle) . However, they have to be charged
which is 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.
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