ECN Forum Forums General Topics of the Trade Non-US Electrical Systems & Trades 220/230/240V 60Hz Systems

Back in the 70's when I was there South Korea used 100/110 volts 60Hz with US type plugs and sockets. They have now upgraded to 220v with Schuko type plugs and sockets. Presumably changing frequency as well would be too much of an upheaval.
I imagine the same or similar has happened elsewhere.