An electric fence is made from three elements:
- Energiser – This generates a regular pulse of electrical current
- Wire – This conducts the current
- Earth – Returns the current back to the energiser
The energiser sends a pulse of electrical current down the fence wire. When an animal touches the wire their body completes the circuit. This allows the electricity to flow down to the ground and back to the energiser via the earth stake. The pulse lasts for a fraction of a second, the animal only feels a very brief shock. This causes them to move away from the electric fence immediately.
Most animals will receive a shock within the first week of a fence being erected. It is completely safe but animals dislike the sensation, deterring them from approaching the fence in the future. An electric fence is really a psychological barrier, so you can use fewer materials than a physical barrier, keeping cost to a minimum.