I have one who would just go right through the tape. Problem was the output of the charger. It was sufficient for dogs really, but not for a determined horse. I bought a 15 joule AC unit that is rated for bulls and other large strong animals. He touched it 2 times, not again. The first time he touched it, he walked up like he was going through it.....uh HUH! You could hear him grunt all the way back to the barn. Second time, he walked up and sniffed it and touched it with his nose. He ran like he'd been bit by something. Hasn't offered to get close to it since. Everybody else respects the 1 joule type but oh no, not him, he gotta have the strongest one Zareba makes. I also put up the the Dare Heavy Duty Equi Rope, breaking point 1592 lbs. And it STRETCHES a lot before it breaks, so it's gives a lesson that's not soon forgotten. Charts and Guides < Electric Fence Resources | Zareba
I forgot to mention, I have a common fence with a neighbor that has barb wire too, I just put the T posts 3 feet inside the fence line and used the caps and 5 in. Extended length t-post insulators to add some distance. He WON'T get near that barb wire because of the HOT wire.