Yes, two wires, a live and a ground wire would be better. If the horse takes a chance and pushes the upper wire he'll get a good snap, touch the lower one to boot and I promise you he'll do a turn on his haunches you could never teach. Horses can sense when the charger is on and you need at least 2000 volts preferably 3000 or more. If a dumb one tests it the idiot will put his nose on it, and after that you could probably keep him behind string. If you don't have a tester, get one, the cheapest model works altho the dinky little light can be hard to see during the day. The digitals are considerably more expensive but easy to read.