If the 'crushed' wire was between the positive terminal and the fuse then there is nothing to stop a dead short to the case.
That would be true IF only about the ELT. But two( or more ) possibilities still exist
1) somewhere in the numerous junction boxes/electrcial load /transfer/boxes and remote switching could be a sneak circuit- by moisture or by abrasion, etc. That would put up to 32 volts from either of two " main" batteries on perhaps the normal isolated cockpit/ data lines to ELT ???
2) early mention of ' sparks" in the A/C unit somewhere- but not clear when. Ground power was connected- but turned off at pad supposedly. IF true that sparks were noticed AFTER ground power disconnected- a whole new story.
IF sparks when connected- then why wasn't it checked out. ( unless there is nothing in check lists for sparks in A/C ???
