Homemade Fence Testers

Fluorescent Bulb Method

• An inexpensive and effective homemade electric fence tester is one constructed from a fluorescent light tube. The tube needs to be in working order with no cracks, though it doesn't need to be brand new. Wrap one of the tube's metal caps with electrical tape until no metal is exposed. Tape a piece of nonconductive material, such as a piece of scrap wood or a branch, to the covered end of the tube to serve as a handle. When you approach the fence with the uncovered end of the bulb, it will light up if electricity is flowing.

How it Works

• Fluorescent bulbs feature a chemical vapor that emits light when excited by an electric current. When you approach the fence with a fluorescent light's metal cap, electrical energy enters the bulb and causes this reaction, which a chemical coating on the inside of the tube turns into visible light. You may not even need to make contact with the fence to produce light, depending on the strength of the current.

Safety Issues

• The length of a fluorescent tube, which can be anywhere from a few inches to several feet, allows you to keep your distance from a potentially live fence wire while testing it. Adding a wooden handle and wearing a heavy glove will give added protection against shocks. Other testing methods, such as touching the fence with a blade of grass or plant stem and listening for a cracking sound, bring you much closer to the fence and increase the chances of a painful shock.

Alternatives

• If you need to test your electric fence often you may be better off investing in a commercial fence tester. These devices are available for just a few dollars and feature non-conductive plastic handles. Another option is a fence tester that is permanently installed on the fence itself. These testers hang from fence wires or mount to fence posts and detect the presence of electricity. Unlike a homemade tester that uses a fluorescent bulb, a permanently installed tester will light up only when the flow of electricity stops, alerting you to a problem.