How electric fencing works
An electric fence is a psychological barrier that keeps farm animals in and wild animals out - even over long distances.
A pulsed electric current is sent along the fence wire, about one pulse per second, from an energizer which is grounded. When the animal touches the fence it completes the circuit between the fence and the ground and receives a short, sharp but safe shock. The shock is sufficiently memorable that the animal never forgets.
Because the electric fence is a psychological barrier, it does not require great strength to be effective. However, it must be well designed and constructed to absorb some pressure from animals, snow and wind. The energizer must have enough power for the length of the fence and for the animals being controlled.