A Guide To Fitting Electric Fencing
What does an electric fence system consist of?
The principle on which the electric fence works – and what differentiates it from other fences – is the animals’ reaction to the electric shock they receive when touching the fence. The electric shocks are not dangerous to either humans or animals, but nonetheless make them afraid of coming into frequent contact with the fence. This works in respect of all types of wildlife – both in containing animals as well as in protecting against them.
An electric fence circuit consists of 5 main parts:
① The energiser produces regular current pulses.
② The fence wiring transports the current along the fence. Insulators ensure that the current is not led away to the soil.
③ When an animal touches the fence the current travels through the animal’s body.
④ The current travels through the soil.
⑤ The earth stakes carry the current back to the energiser.
Three factors decide on the optimal function of your electric fence
Long lengths of electric fence can only function using fence wiring with good conductivity. When using 4 wires of 2.5 mm steel, fences up to 120 km can be considered when there is no vegetation. Using only one wire of the same, the maximum length drops to 30 km.
If you go down to one compact-polywire that has 6 x Ø 0.20 mm stainless steel strands, the maximum length of fence goes down to 250 m. If there is vegetation at the fence, then these figures drop considerably. Depending on the desired fence length and the anticipated vegetation level the fence wire must be selected carefully.
In longer fence lengths, only high conductivity fence wires ensure maximum performance to the end of the fence.
The Basics of Earthing
An electric fence is a circuit in which current flows. The current which travels through the wire, the animal and through the ground cover into the soil, needs to flow back to the energiser with the help of earth stakes.
As the soil is a poor conductor, particularly when it is dry, sandy or stony, it is important to ensure an adequate earth system, so that the energiser can reach its full performance.
1 For permanently installed mains and battery energiser, 3 earth stakes of 1–2 m in length are generally sufficient.
2 For portable battery energisers there should be at least one earth stake of 1 m in length. Additional stakes are recommended in dry conditions.
3 Ensure that all connections are made using screws.
4 All parts of the earth system should be
hot-dip galvanised – i.e. rust proofed!
5 Check the earthing of your energiser regularly.
The standard earth system for energisers from 1 to 5 joules:
Drive 3 galvanised earth stakes of 1 m length into the soil 3 m apart and
connect them with screws and high voltage cable.
An efficient energiser is the foundation of the basic power supply to your electric fence. The output power of an energiser is specified in joules.
Four factors play a crucial role when deciding which energiser to use:
① Vegetation load on the fence
② Fence length or number of wires
③ Type of animal
④ Power supply 9 V / 12 V or 230 V