Fence Fast  is an effective and safe way of controlling animals. However, a number of factors must be taken into account to get the best results from electric fencing: broken or damaged insulators can leak electricity, poorly grounded energizers fail to function and weeds or vegetation on the wires drain the current, making the fence ineffective.

A power energizer (shown above) generates electrical pulses on one of its terminals, and sends them along the charged wires in a short rhythm of about once every second. The other terminal is connected to a metal rod implanted into the ground called a ground wire. When a person or animal touches the charged wires and the ground at the same time, an electric circuit is completed and they receive a shock. The effects of this shock depend upon the voltage, the energy of the pulse, the degree of contact between the recipient and the fence and ground and the route of the current through the body; it may be barely noticeable, uncomfortable, painful or lethal.

Shockingly Effective: The Benefits of Electric Fences for Home Security

Because the pulses are very short, many people and animals can escape the shock by running through the fence quickly between pulses or by pushing other individuals through the fence with their woolly coats (which act as a good electrical insulator). Those who do not avoid the danger can be killed or badly injured. In addition, a person touching the fence with bare feet may be severely shocked. This can be avoided by adding a ground system, consisting of multiple metal rods buried in the soil and connected to the hot wire via a ground wire.