Motorcycle Repair: What could be causing my coils to rupture?, stock coils, two different things

Question
Ihave a 76 xlch. I have been through three coils and I cant find the problem. The coils keep rupturing. All my wires are hooked up properly and I have 12 volts to the coil. I left the key on for only 15 minutes without the bike running. When I came out I went to start the bike and when I did, the coil insides melted and gooed up my frame pretty good. The latest coil was a screaming eagle 2002 coil. The first two were stock coils. One was a 76 and the other was a 72. I have ohm'd out bot the points wire, and the hot wire. Only the hot wire gets tone. The points wire does not. Both plugs have been replaced as have been the plug wires. Have you ever heard of coil's rupturing and cracking and if so ...how do I fix it.

Answer
Coils crack from two different things. One is having power to them without the bike running. 12 volts going in and around 20,000 volts not going anywhere. the other is to much voltage.
Check to make sure the power is off to the coil when you turn the key off. If you leave the key on it will crack the coil in a very short time
Go0od luck and happy riding
Mike