The UK has 240 v at 13A for mains, however, having stuied electrical engineering at college, (granted sometime ago) it is te current that is dangerous, not the voltage.
Hence we have 3 pin plugs, (earth pin) fuses in the plugs and now RCD devices in place of a metal fuse box, they will cut the circuit instantly a problem occurs.
What would it take to upgrade the entire US infrastructure to 220/240 volts ?