Nicholas Bodley wrote:

Speaking of rare wire types, only once since 1942 have I ever seen two-
conductor cable (including line/mains power cords) that had no way to
distinguish which wire was which. Otoh, inside a Hammond tonewheel organ,
and (late 1950s) perhaps most electric-action pipe organs, multiconductor
cables had no wire ID. (I don't know about cables between consoles and
the organ proper, though.)

Here in the UK I've a Desk fan I inherited from my grandparents that has a
mains cable with no distinguishing marks - the cable is like a 3 core
ribbon cable with clear insulation on all 3 wires (no outer insulation),
when I was a kid I once stayed with gran in the summer and wanted to put it
on to cool the room and found someone had taken the plug off. Without
access to a multimeter I had to disassemble gran's torch and use the
battery and bulb to find the earth wire and guess the other 2. As far as I
know the plug's not been changed or rewired since.

But then again it's got no guard round the fan blades either (but motor is
so weak the blades stop easily when touched) - wasn't health & safety
ruling much more fun years ago (I've no idea how old it is, I'm guessing
40's or 50's).