Here's a 120 Volt receptacle with a 240 Volt supply behind the faceplate. I would not have spotted this as it was in the garage behind an appliance. The owner had stated that they had plugged in the garage fridge and burned out the motor. No wonder.
At some time in the past the outlet was used for 240 Volt service, likely for an appliance that came from an off-shore household move.
A very dangerous situation that required immediate correction. As this inspection was also in advance of the building's two year construction completion anniversary, it was included in the list of defects that could still be claimed and corrected under the new home warranty program.