Install electric fence

WHAT IS AN ELECTRIC FENCE?

An electric fence is a technical solution to containing all types of animal and protecting crops, keeping animals in or out.

IMPACTO MULTI

An electric fence allows to controls animals by means of brief, high voltage electric shocks. These electric shocks produce unpleasant pain (the more powerful the energiser, the more intense), which stimulate the animal’s memory, making it respect the fence.

ELECTRIC FENCES CONSTITUTE NOT ONLY A PHYSIC BARRIER, BUT ALSO A PSYCHOLOGICAL ONE

ADVANTAGES OF THE ELECTRIC FENCE

• Easily constructed, it needs less work and materials than conventional fences
• Offers more flexibility when dividing pastures, thus improving productivity.
• Makes possible the comfortable setup of temporary fences, thanks to its agile and simple installation process.
• Allows the control the animals inside the fence, minimizing those damages that other types of installation may inflict on the animals, for instance barbed wire.
• Effective system for protecting crops, plots, fences, etc, thanks to its dissuasive effect on wild animals

What are the different types of energisers?

Amongst the first questions rising, if not the first one, on building an electric fence is, what energiser to choose and what options are available. Despite the great variety of choice, energisers can be divided depending on their power source:

• 9 V dc from a non-rechargeable battery
• 12 V dc from a rechargeable battery
• 12 V dc from a solar module and a rechargeable battery
• 220-230 V ac from the power outlet

As rule of thumb, a 230 V mains energiser is the best option, when such a supply is available, due to its low acquisition and operating cost, optimum power, reduced consumption and ease of operation.

If there is no mains connection available, then the second best alternative is a 12 V rechargeable battery with a solar module. This sort of equipment provides an acceptable amount of power and its cost of maintenance is low. The utilisation of solar modules yields more autonomy, which is particularly useful in case of powerful energisers and/or placed in isolated places./p>

If the area to fence is small and/or we need move the energiser quite often (e.g. rotation pastures on different grounds), our choice should be a 9 V or 12 V battery energiser. These energisers have a rather limited amount of power, since they run on a smaller battery with less autonomy

9 V Battery energisers can have an autonomy of up to 9 to 12 months using a long-life non-rechargeable alkaline battery (1000 W), whereas 12 V battery rechargeable energisers have an operating mode similar to mobile phones (i.e. periodical charges).

How do I choose the right energiser for my fence?

The success of our fence depends to a great extent on selecting the right energiser. In order to pick out the best suited to our needs, we need to bear in mind the following aspects:

• Fence length: the perimeter of the area to fence in is one of the most important factors; the longer it is, the more powerful the energiser must be
• The type of terrain: the quality of the soil is also important; dry, sandy or stony soils need more powerful energisers and a better earth system than moist, earthy terrains.
• Vegetation: clean pastures with light vegetation touching the fence wire occasionally require a less powerful energiser than those, where there is heavy vegetation continuously coming in contact with the fence wire
• Animal type: animals fall into two categories according to sensitivity towards electric fences. The most sensitive animals such as cattle, horses, pigs, dogs, cats, etc are easy to contain, thus requiring less powerful equipment. On the contrary, less sensitive animals like, sheep, goats, wild boars, poultry, etc are difficult to contain, and therefore they need powerful energisers.

HOW TO INSTALL AN ELECTRIC FENCE

Electric fences can consist of a closed circuit, beginning and ending at the same point, or an open circuit, beginning and ending at different points. In the first case, the energiser must be placed ideally in the middle point, in order to obtain the largest amount of energy on the line.

9 and 12 V battery energisers may be in the open air, since they have been designed to that end. Any additional protection will help to their maintenance.

Solar energisers must be placed in sunny areas, oriented towards the south and free of shades as much as possible. It is recommended to clean periodically the solar module surface to remove any dust accumulated.

Mains energisers must not be left in the open air; they are best placed somewhere high and protected from the rain, for example below an eave.

FENCE LEAD CONNECTION

The energisers are provided with a lead connection cable (red). This cable is connected to the lead terminal on the energiser and then to the fence. If the cable supplied isn’t long enough, a high tension or “double insulated” cable must be used. Never use electric cable with inferior insulation (like that used in domestic installations)

THE EARTH SYSTEM

Earthing is the most important part in the construction of an electric fence. It is formed by a series of metallic stakes, buried underground and connected to the earth terminal (black terminal). The electric current gets out of the energiser, flows through the conductors and comes back closing the circuit, when the animal touches the conductors.

HOW TO EARTH AN ENERGISER

• Install the earthing at least 10 m away from any other earth system (home or farm) and at least 20 m from a milking station’s earth system.
• Use metallic stakes resistant to rust. Hot dip galvanised pipe or aluminium are ideal choices. Rust greatly reduces the effectiveness of the system.
• The number of stakes to use will vary depending on both the energiser’s power and the soil’s condition. As a rule of thumb it may be used: a stake of one meter in length for energisers up to 2 Joules, two stakes for energisers up to 4 Joules and three stakes for energisers up to 8 Joules. In sandy or dry terrains the amount of stakes must be increased (see “ an alternative earth system”)

AN ALTERNATIVE EARTH SYSTEM

In those terrains where conductivity is low (dry, sandy soils or full of gravel), an alternative method for achieving a correct earth system is installing an earth return wire.

This system consists in connecting one of the conductors to the earth terminal on the energiser, thus when the animal nears the fence, it will touch both the live wire and the earth wire, receiving the highest electric shock possible.

TESTING THE EARTH SYSTEM

In order to test the effectiveness of the earth system, we must short the fence out at least 100 m away of the earth system, by using several metallic stakes between the live wires and the ground, thus diverting the current flow. At this point the fence voltage should be 1.500 V (1,5 kV) or less.

Using a voltmeter or a fence tester we will check that the voltage between the wire connecting through the earth stakes to the energiser earth terminal and an independent earth stake. The reading should be below 300 V (0.3 kV), otherwise we should add more earth stakes or change their location.

FENCE CONSTRUCTION

When selecting the kind of materials to use, we need to bear in mind whether we are building a temporary/mobile fence or a permanent/fixed fence

• Posts:permanent fences are usually built with wooden or metallic fences, due to their resistance and durability. The last years have seen a growth in the use of recycled materials too.

  Temporary fences are usually made with iron metallic rods (like those used in the construction sector), but plastic posts are highly recommendable. They are agile to mount due to their low weight and easy to install.

• Conductors: : permanent fences are usually built with galvanised steel wire or aluminium wire. Galvanised steel is an economical option with high tensile strength. Aluminium wire stands out for its high conductivity, which makes it ideal for building long fences.

  Mobile (pasture rotation) or temporary fences (crop protection) are usually made with polywire and polytape. They are wire and tape which combine metallic cables and plastic in order to obtain high conductivity, good tensile strength and easy handling. Polywire is usually made of stainless steel - less conductivity, but higher tensile strength - or tinned copper - higher conductivity and good tensile strength.

  Polytapes are not only good conductors, but also have better visibility, which reinforces the electric shock effect. This is particularly important as far as horses are concerned, whose sight is worse specially at dusk

• Insulators: conductors must not make contact with branches, grass, bushes, etc at any time, as it would reduce the fence effectiveness. To this end insulators support the conductors and prevent them from touching anything.

  The choice depends on the type of post selected: wood (Z-1, Z-2, Z-5), metallic rod (Z-4, Z-8, Z-9); and to a lesser extent the kind of conductor: wire, polywire or polytape.

  We must bear in mind, if there is already a fence in place, whether barbed wire or metallic netting. If so, we must use offset insulators in order to avoid the current diverting to the ground (Z-60, Z-61, Z-63, Z-64, Z-65).

VERY IMPORTANT