I had a horse that could open electric fencing. The handles had to be turned just right and a reinforced clip for them. Otherwise he'd specifically grab the handle and rip upward until it yanked loose. He escaped his stall one night, broken in to the fee area, and ate himself to severe laminitis on a 55g drum of oats. We tried to save him but he had other problems pointing to a metabolic disorder so once foundered and getting out of shape from lack of exercise he started to succumb to further episodes due to heat or managing to eat too much clover. Eventually he was put down.