I was not aware of this '32VDC bus', can anyone enlighten me?
However - and this is making the assumption that the ELT was indeed the cause and not a victim - all the 'evidence' we have to date makes the most likely cause internal to the ELT. Given the way these things should be protected, for instance if there was a failure mode that could lead to data lines 'back-feeding' the battery a diode would be fitted, likewise a non-resettable fuse in the battery pack to protect against overcurrent, it almost sounds as if the wire that got 'pinched' was within the pack itself and upstream of the protection. That would not be good but I can't see how it would have got through a design review - it's the sort of thing one focuses on big time in battery powered equipment!.