This also brings up an interesting issue I wondered about a year or so ago. What if you had to choose a receptacle and plug type for a 240 volt circuit that was wired with a hot at 240 volts relative to ground, and a grounded conductor? Using a 6-XX configuration might not be safe. Something could be plugged in that could not handle the way it was wired. I'd say the 7-XX configurations would be safe in the sense that they would be designed for at least that much voltage (and more) and for the single hot and grounded conductor combination. But even that could pose a hazard if you put a 7-15P on something that can only handle 240 volts. If pressed to do so today, I might use a German Schuko configuration instead, or maybe the British or Australian configuration.
