I had a 1920s house (US, so 110v standard) that would put 220 to the light over the stove if you turned on the garbage disposal while the microwave was running. Burned out a lot of incandescent bulbs. Made the first CFL I put in explode at the base.
There were also outlets with constant 110 between neutral and ground, 220 between live and ground.
I spent a lot on wire for that place.