A 240v outlet in the US is really no more dangerous than a 120v outlet. They both present 120v to ground with about 200x the current necessary to kill you.
Bear in mind, most of the western world is living with 230v outlets for most consumer grade equipment.
They think our 120v standard is archaic and inefficient.
These 120 vs 220v arguments come up quite often in discussion groups that include Europeans and "down under" folks.
I think the 120v thing got standardized here during the voltage wars when Edison said AC was too dangerous in the home. He wanted everything ti be DC but the problems with long distance transmission sunk that idea. Now that reliable solid state inverters are available that is less of a problem and some long distance transmission is being done with DC.
For most folks that technology shows up as that charger/power supply block that is too light to have a transformer in it. They are generally "wide mouth" supplies that will work with almost anything you can throw at them.
typically 100-250v 50-60hz. Most of them would also work with 140-300 VDC since the first thing they do is change the input voltage to DC but it is likely to be polarity sensitive if it is not a bridge rectifier.
