Electric fences and building enclosures
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 Electric fences
Electric fences can be a very effective option for keeping foxes at bay. While they may not seem at first glance the ideal option for the urban setting they are suprisingly useful. They have a number of advantages over other methods.
- Easy to set up, as they don't require you to do any major alterations to the garden.
- They can be simply removed if you're not sure how long you will stay in a house.
- Gives a fox an unpleasant surprise which discourages it from attempting to gain entry at the same point.
Electric fence systems consist of two major components, firstly the fencer, and secondly the fence its self.
The fencer is the electronic device that puts the charge on the wire of the fence. Every n times a second the fencer will send out electric pulse along the fence. There are two main types of fencer: battery, and mains. The battery fencers are normally run from a car battery with each charge typically lasting 2-4 months. The main advantage over the main ones are portability, and the fact that they can be fully contained in the garden with no need to run wires in and out of your house. The mains fencers require a mains supply to operate, they have the same kind of power a battery based one has with the only advantage being you don't have to worry about charging it, as needed with a battery, although during a power cut your fence will not work.
 The Fence
The fence consists of a number of wires that carry the electric charge, when an animal touches a wire the electric charge will travel though the animal to the ground causing a shock. If the animal in question is unlikely to be touching the ground or the fence is not earthed in some way, the animal will not receive a shock. To counteract this problem some fences use what is termed a hot and cold wire, with hot and cold wire being strung quite close to each other. The hot wire is the one connected to the fencer and is carrying the charge, while the cold wire is connected to an earthing rod (a big metal rod hammered into the ground). When an animal touches both wires the charge travels from the hot to cold wire though the animal, thus causing a shock. This hot and cold wire system can not however be used in areas that are open to the general public, due to the regulations covering electric fences.
- Myth : The shock will kill small animals.
- Answer : While the voltage on an electric fence is very high (about 10 000 volts), there is a very small current (about 10 millionth of an amp). It is amps (current) that kill rather than the voltage (potential difference). Small animals will only be surprised, not killed.
- Myth : The fence will injure small children.
- Answer: As with the myth above amps injure, not volts, an AA battery has a higher output in amps. Whilst causing no injuries or pain it is very surprising and may cause some small children to cry if they touch it. This is however a mistake the child is unlikly to repeat! Fussing parents are more of an issue!!!
- Myth: The fence will kill all the plants near it.
- Answer: About 50 years ago a version of an electric fence called the weed burner was popular with american farmers. This version used a high ampage on the wire to burn any weeds growing at the bottom of the fence. However this did have a tendency to start grass fires in very dry areas, so is no longer used much. Comercially in the UK there are very few weed burners you would struggle to find one, even on e-bay.
 Obtaining the equipment
There are a number of suppliers in the UK of this type of equipment, typing "electric fence" into google will find many useful results. However many second hand and new systems can be found on e-bay.