Spotted behind a small strip mall during one of our walks:
Perhaps the cable wasn’t rated for outdoor use?
The earth ground conductor isn’t insulated and the nonconductive filler strands look scary, but neither should kill you outright.
As far as I can tell, the insulation around the individual conductors remains intact, but it’s surely brittle and ready to fall off at the slightest touch.
The breaker box and cable are out of reach and, I suppose, out of mind.