I had an appliance repairman look at a fridge today. He made a minor adjustment and we plugged it into an outlet not normally used. Then he had one hand on the metal hinge of the fridge and one hand on the oven. He got shocked and the handle was showing 120 volts on his meter.
He thought that there was reverse polarity at the outlet, but wasn't sure. I called an electrician who will be looking at it on Saturday.
In the meantime, the appliance repairman told me that I can buy a device to check outlets for polarity.
Do such devices work well? I want to avoid this problem, because the shock could have been a lot worse.