Very surprised to hear 120 volt was ever used in Europe. Always knew Japan had 110vac though.
Standard service is 240 volts in UK/Europe, just like US 240, but its just 2 wires (line and neutral) and 50 Hz, not 60.
For industry and commercial use in Europe, 220/380volts was the early wye and 240/415 the present wye 3-phase voltage, which use a neutral conductor.
US has 3-phase in 2 standard wye configurations (208/120 and 480/277) Canada uses 600/347 wye instead of 480/277, as if that weren't enough.
USA, prior to WWII, used 220 three phase delta with no grounded conductor, just an equipment ground. 440 also used as a delta in larger users. I will spare the details on two-phase and 25 Hz, since it was early but appropriate for the times then.
Last, there is the 240/120 volt three phase delta, where one of the phases (usually B) is the "wild leg" and the other two, A+B are each 120 volts to neutral. This requires separate 240/120 single and 240 three-phase circuit breaker panels.
Lastly - Salute to both Nikolai Tesla and George Westinghouse, co-inventors of three-phase ac power!
