The functionality of an electric fence - production of electric shocks when the fencing wire is touched - can be explained as follows. The fence wire is connected to one lead in the controlling device, the earth connection to the other. The quality of the wire is insignificant. As the voltage is relatively high it must, however, be selected with consideration to the animals to be fenced.

The electric shock experienced by the animal is the difference in voltage between the fencing wire and the earth. The connection in this instance is the animal that touches the earth. A bird sitting on the fencing wire with no connection to earth will thus not feel the shock.