This electric fencing line tester could not be simpler to use push the earth prong into the ground and then touch the tester wire to the fencing tape the bulb will light up to indicate the fence is live unit also has a test button size 85mm x 20mm simple and easy to use earth prong live indicator bulb test buttonhere are the top ten rules to make your electric fence work properly1 keep your fence as free from growth as possible growth impairs the output of every commerc