It's possible that connection had simply worked itself loose.
Large current through a loose connection could equal lots of heat (I squared R losses).
(edit) My Land Rover has a connection for easy jump starting that was prone to loosening up. It was a known case of several under-hood fires in that model.
Large current through a loose connection could equal lots of heat (I squared R losses).
(edit) My Land Rover has a connection for easy jump starting that was prone to loosening up. It was a known case of several under-hood fires in that model.