Coil keeps frying

Hello, I am new to the forum and really need some help. I have a 92 325II have replaced the #5 coil with 3 different brand of coils and the keep burning through the case of the coil. I have replace other coils on the other cylinders and the are fine its only on the #5 cylinder it keeps happening to.. The the engine light comes on and with not flash any readable code it will either stay on or just keep flashing in no order just on and off with no delay any ideas? Thanks in advance