An electric fence is put up to keep animals such as horses, cows or other grazing animals in paddocks or pasture areas. They can also be used to keep animals like squirrels, cats and dogs out of places like gardens or lawns. These fences all work by a closed circuit technique. Ground rods are first put into place, so that when the fence is energised and the circuit is closed by touching the fence, the resultant electricity will flow through the ground and complete the circuit at the ground rod. The person or animal that crosses the circuit in this way, receives a mild cautionary shock.
Pick a good thick blade of grass anywhere on a lawn or in a field. A crabgrass leaf works exceptionally well and it should be at least 4 inches in length.
Stand next to the fence to be tested while holding the grass at the base where it has been picked.
Gently touch the tip of the blade of grass to the electric fence. If you get a slight tingling sensation in your fingers from the electricity, the fence is working. If there is no tingling sensation, the fence has shorted out somewhere and must be repaired.
All commercially made electric fences for farm and home use, have high voltage but low amperage. Therefore, even the most powerful of these fences will only cause a shock when actually touched by either an animal or a human.
Never grab onto an electric fence or use a wire or other metallic item to test an electric fence in this way. All institutional electric fencing, like prisons and government facilities, are non-testable by any means and must be avoided at all times.