How does an electric fence work?

The positive terminal in the energiser sends out a charge. It is normally connected to the electric fence tape.

The negative terminal on the energiser is generally connected to the ground via a metal rod (called an earth stake) driven into the ground at least 900mm.

For as long as the electric fence wire and the earth don’t touch, electricity won’t flow as there is nothing joining them. But once something that is standing on the ground also touches the wire, then the circuit is complete and electricity can now flow from one terminal to the other. The animal touching the wire is the conductor between the fence and the earth.

Energisers send out pulses of electricity - generally about one every one to two seconds. The fence is not permanently live like your power sockets in the house. This enables the shock sensation to occur and then stop – allowing for the animal to step back.

For a shock to be useful, it needs to cause a muscle in the animal to contract which means the shock needs to be across the entire muscle, not just part of it.