The problem presented itself when the fuse blew 3mo ago that was connected to our TRANE split system heat pump TWR030C100A0 on 3 separate occasions. We flipped the breakerand everything switched back on and held for weeks at a time. This last time it would not stay on. We replaced the fuse and it held long enough for us to see sparks in the unit itself and cut power on our own. The sparks areleaving a burn mark directly next to the bolt near the bottom that holds on the piping for the freon. The closest wiring is 12in away. Any one have a guess as to where this current may be jumping from?

Leave unit off and call for professional help. These type issues are not diy

Take esquire1's advice and call a professional. It may be the electrical connections at the compressor, repairable with a stake-on kit but too risky for a d.i.y.'er.