Originally Posted by Timex
MY PI surge protector wouldn't let reverse polarity thru.
I'm Mike Sokol from the No~Shock~Zone. First let me note that what's commonly referred to as "reversed polarity" is actually swapped Neutral and Hot lines in an AC circuit. The polarity actually reverses itself 120 times a second anyways. So appliances that use AC power really don't care if the Neutral and Hot lines are reversed or not. That means that AC "reversed polarity" won't cause your refrigerator to operate less efficiently, nor will it damage power switches or any of of the other dozens of rumors I've read about.
And if everything else is wired properly, swapped H and N wires won't cause a hot skin condition by itself. But that condition is very dangerous for any technician working on it since they may assume the Neutral wires aren't energized, when in actuality they're 120 volts about earth potential.
But, and this is a BIG BUT... swapped N-H (revered polarity) wiring in addition to a bootleg ground is VERY dangerous since it creates a hot-ground condition can't be detected by any standard tester in existence. And as I've noted numerous times, if an electrician can't even wire an outlet with correct polarity, how can we trust that the rest of his wiring is correct?
If your tester/protector is tell you there's a reversed polarity condition, it's possible that your extension or shore power cord has been reversed somehow during a repair. I've not ever heard of a factory built extension cord being built with revered polarity, but I've seen some crazy stuff so anything's possible with imported products.
If you want to learn how to test voltage and polarity yourself, here's a video I made on the proper technique.