Fencing instructions for apiaries 2010

Text and photos: Pekka Karoniemi

The aim of these instructions is to provide information about the available equipment, its suitability for different locations and installation in order to minimise the need for future fence maintenance. Fences installed and maintained according to these instructions have been effective in deterring bears from apiaries with only a few exceptions. Reasons for these have included equipment failure and bears digging under the fence, for instance.

Equipment alternatives in Finland,  manufacturer Farmcomp Oy:

OLLI 100  for mains-powered locations. Voltage 6,500V, maximum pulse energy 1.2J and power consumption 2W.

OLLI 70B  battery-powered energiser for shady locations with no mains power. Voltage 9,900V, maximum pulse energy 0.65J and power consumption 105mA. A 12 volt 60Ah battery thus requires charging approx. every three weeks. OLLI 70B energiser is run at the maximum voltage.

OLLI 70B  6 watt solar panel and 12 volt 60Ah battery for locations where solar power can be utilised. At a location with no shade, the battery requires hardly any charging during the summer. In the autumn, it is important to ensure that the battery is properly charged due to a danger of freezing.

OLLI 70B  energisers use a 12 volt battery as the primary power source. Both OLLI 70B equipment combinations can be connected to a 140Ah air-activated alkaline battery which functions as a 9 volt back-up system. The battery is disposable and non-rechargeable and has enough power for approx. two months. The alkaline battery has a protective tape on it, tape must be removed before use.

If the battery still has power at the end of the season, seal the air holes with suitable tape for the winter. Energiser 70B automatically switches to the 9V battery, when the voltage of the 12V battery decreases to 11.50 volt. OLLI 70B energisers have deep discharge protection, but the battery life can be increased considerably by charging the battery when the voltage has decreased to approx. 12.20V. Well-maintained batteries have lasted a minimum of six years in field tests.

To erect the fence,  you need a 1-2kg sledgehammer to drive the posts and earthing rods into the ground. A knife or pliers are needed to cut the electric tape. The electric fence tape has five metal conductors. A fence voltage tester or a multimeter which can measure the voltage of the fence and the battery can be helpful for installation and maintenance.

Fencing Instructions

Most fences are built for existing apiaries so lighting conditions are not always optimal. The need for maintenance charging is lowest at locations with a south-facing, no-shade sector with a 180 degree field of view for a solar panel. Erect the fence at a minimum distance of 1 metre from the beehives and ensure that you leave enough working space around the hives. Do not place the hives at the corners of the enclosure, right by a post or near the energiser or the battery and its connecting wires, because bears often try to enter the apiary where the fence is closest to a hive. Tighten the electric tapes as shown in the picture.

The fenced area should be mown. Efficient equipment for this purpose is a brushcutter with a 3- or 4-tooth metal blade; using this allows the cutter to be operated at minimum power. Use goggles and ear defenders when operating a brushcutter. Sharpen all sides of the blades; this allows you to just turn the blade over and thus doubles the operating time before sharpening is needed again. The tip of the blades should be rounded, which allows mowing under the fence right by the posts without a danger of damage to the posts. Alternatively, a string trimmer can be used for mowing. In this case, the brushcutter needs to be run at higher power. Fuel and string costs are also higher than the costs of using a metal blade. Small areas can be mown with a scythe.

If you erect a fence with several sides, thread four electric tape reels onto a post at a suitable point to allow you to run all electric tapes around the enclosure at once. Four electric tapes are used: the bottom one approx. 15-20cm above the ground and the others at regular intervals up to approx. the height of one metre. Run the electric tapes on the outside of the posts. Do not loop the electric tapes around the posts; this allows you to tighten all the fence tapes by simply pulling the ends.

The red power cable of the energiser is connected to the bottom electric tape with a metal connector; from here the power is conducted to the tapes above. The connecting wire can be attached to the electric tapes above by wrapping it around the fence tapes twice and tying a tight single knot. This decreases the voltage of the top wires only by 200 volt.

A gate is built at a convenient access point. The gate and fence posts are kept close together by cord or other loops placed at the top and the bottom. See the blue cord in the picture which can be lifted when opening the gate.

The energiser is supplied with the necessary connecting wires for the battery, alkaline battery and solar panel.

To make the corners sturdy enough, drive two posts into the ground separately and then connect them with cable ties at several points. The ends of the electric fence tapes are tied with a knot and a slipknot. This makes it easy to untie and tighten the electric tapes.

All fence equipment, including earthing, must be installed inside the fence. The energiser and battery should be placed at a minimum distance of 50cm from the electric fence tapes. Earth the fence so that the fence voltage is 5,000-9,500 volt. The reading on the fence voltage tester between the earthing rod and the ground should be 300 volt or less. The earthing rods should be placed 1-2 metres apart; one rod is normally enough. The solar panel should be pointed so that the sun’s rays hit the surface as perpendicularly and unobstructedly as possible. The battery requires a rain cover and also a surface underneath which prevents it from freezing to the ground in the autumn. The energiser package includes an electric fence warning sign which can be threaded onto the top electric tape.

Bears can cause damage during early spring even before the snow has melted. Apiaries at the greatest risk include, among others, those which have suffered bear damage or which bears have attempted to enter in the previous year. Building protection for these sites should have the highest priority. Most attempts of bears to enter apiaries can be avoided by following these instructions for fence construction. The photo shows how a bear has dug the ground by a beehive up to the fence.

Maintenance of the electric fence

An electric fence is not a physical obstacle for a bear, but it does provide a deterrent by electric shock.

During the season, maintenance should focus on the following factors which disrupt the functioning of the fence.

1. When vegetation touches the bottom electric tapes, the energiser dries it up and the fence functions relatively well in dry weather. Dew and wet vegetation in rain, however, conduct much of the energiser's power into the ground through the vegetation, which means that the fence may no longer be powerful enough. The vegetation must therefore be trimmed as soon as it reaches the bottom tape.

2. The charge of the battery and alkaline battery must be monitored either on the basis of time passed or by directly measuring the charge of each. Clean the surface of the solar panel when necessary and tighten slack fence tapes. During the winter, store the energiser, solar panel and fully-charged battery indoors.

After approx. ten years, the electric fence tapes will start to deteriorate and their conducting ability will not compare to that of a new fence. Replace the electric tapes at the latest when the electric conductors start to break, and consequently, the fence tapes are making a snapping noise at the pace of the energiser’s pulse. You can also hear the same sound if one of the connections is not tight enough.

For more information about the equipment and fences, visit www.farmcomp.fi.