Printed from: https://conservationhandbooks.com/fencing/electric-fencing/
Electric fencing was originally developed as a way of providing a temporary, portable fence, which could be moved daily to give dairy cattle access to fresh grazing. A large number of products are now available for the permanent and temporary fencing of cattle, sheep, horses, deer, rabbits and other animals.
Advice on electric fencing is available from manufacturers and suppliers of electric fence equipment.
Electric fencing is mainly a pyschological, and not a physical barrier. It follows therefore that:
- Stock must be trained to respect the fence. Young or untrained stock may rush and break through an electric fence, because they have no fear of it. Generally, electric fencing tends to be less effective on wild animals because they have less opportunity to learn respect for it.
- For most animals, an electric fence needs to be operating to be effective, as otherwise they will soon realise they can lean over or break through without getting a shock. Electric fencing is not normally strong enough to be stock proof without the deterrent of the electric shock.
- Electric fencing needs regular checking by someone who understands the system. Unlike conventional fencing there is little margin for error, as if a fault occurs, the entire ‘barrier’ may be lost. Most types of conventional fencing will keep functioning as some sort of physical barrier, even when not perfectly maintained.
- Electric fencing components are lightweight compared to conventional fencing, which keeps down costs and erection time.
Electric fencing works by making a circuit between energiser, fence, animal and ground. The output along this circuit is weakened if current is lost through long vegetation or stray wires touching the live wire. It follows that:
- Electric fencing will not function efficiently through lush vegetation, or where animals are grazed only on one side of the fence. Fences which have woodlands, arable land, roadside verges or hedges on one side may not be suitable. High powered energisers will burn off grass growth, but scrub or woody growth may encroach, particularly where fences are not ‘live’ all the time. Rushes and bracken can also cause problems, but heather has little effect on shorting-out fences. Part-electrifying, using scare wires or top electric wires may be suitable, as these can more easily be kept free of vegetation.
- Electric fencing will not function against animals which jump the fence, as they will not receive a shock. A scare wire attached to one side may be effective, or alternatively a separate electric fence set about 1.2m (4′) to the attack side of a conventional fence, wall or hedge may discourage deer from jumping.
- Some animals are more sensitive than others to electric fencing, because they present little electrical resistance. Most animals will first touch the fence with their noses, which being moist, conduct the current effectively to the ground to complete the circuit. Pigs have wet noses and good memories, and may refuse even to cross lines where electric fences used to be. Dogs are also usually very sensitive, which can be useful against strays, but requires careful handling of working dogs. Sheep, on the other hand, may feel little effect through thick fleeces.
Permanent electric fencing of boundaries and fields is possibly best suited to large areas of stock land, particularly in the uplands. Here the advantages of lightweight components, easier transport of materials and saving on erection time can be gained, without the problems of lush vegetation growth. Simple components are best, in order to withstand the extremes of temperature and weight of snow experienced in the uplands.
Combined electric and conventional fencing
This comprises one or more electric wires combined with a conventional fence. This has several advantages:
- It increases fence life by keeping animals off the fence, and stops damage from them leaning and rubbing on the fence. In this it is much more effective than barbed wire, and is less damaging to both animals and people.
- On new fences, an electric wire can be combined with high tensile netting or wires to give a relatively lightweight but stock proof fence.
- An electric scare wire can be used to stock proof an existing fence, wall or hedge.
Electric fencing is primarily of interest to large scale stock farming, but it is also useful for combining traditional stock grazing with the management of land for conservation, wildlife and amenity. Electric fences can also be used against deer and foxes.
- Temporary or permanent fencing of grassland, heathland and other open areas of land, to allow grazing to be used as a method of management. Grazing helps to reduce the spread of scrub and trees, and is essential to the maintenance of many open habitats.
- Temporary electric fencing can be used to protect newly laid hedges, or as a ‘stop-gap’ measure to keep walls stock proof until repair can be done.
- Temporary or permanent electric fencing can be used to discourage deer from entering newly-coppiced or newly planted woodland, or to protect natural regeneration.
- Temporary or permanent electric fencing can be used to keep rabbits out of new or regenerating woodlands.
- Electric fencing can be used against foxes, to allow the raising of free-range poultry and the outdoor rearing of piglets, and to protect pheasant pens.