February 13, 2014

How does an electric fence work?

The energiser converts either mains or battery power to create a high voltage pulse.  The pulse is very short and is then repeated about 1 every second.  This pulse is commonly referred to as a shock and is felt by the animal as it touches the fence.  The pulse having travelled through the animal then flows back through the earth to the earth stake hence creating a circuit.  The shock is unpleasant so that it provides an effective deterrent when the animal next comes into contact with the fence.  The animal remembers the unpleasant experience and avoids touching the fence again.

Below is a diagram showing in basic terms how items of an electric fencing system form a pulsed high voltage open loop with the animals being the completing link.

An electric fence will work better if: 

  • a bit of thought is put in when choosing your energiser - this will save time and money in the long term.  Consideration needs to be taken of the length of the fence, the type of animal to be contained and the type of fencing being used.
  • a good earth stake is used.  An earth stake must be pushed as far into the ground as it will go.  It should be away from tree roots and building foundations.  T section earth stakes have a larger surface area and so provide a better earthing system.
  • there is no shorting on the fence – ie the live wire conductor must be insulated properly against wood, metal, foliage etc.
  • the better quality tape, rope, polywire, galvanised wire used the less resistance to the pulse therefore the better zap down the line.

Lets dispel an electric fencing myth!

An electric fence does not have to be set up as a circuit.  In theory it could run for hundreds of miles in one direction.  The only circuit that is created by electric fencing is when the animal touches the fence and hence creates a loop or circuit by facilitating the pulse to pass through it and into the ground!

If you have any questions please ask… we’d be happy to help

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