For anyone who wants to know about the reasons why North America has so many mains voltages, here is a video that can help you understand better:

https://youtu.be/ksrE79uLBaY

Thanks, that's very helpful

I still think our 415/240V system is easier to understand. 415V between phases, 240V phase to neutral. We don't have that centre-tapped delta system. Although just to confuse you, 'wye' is 'star' over here 

I'm talking about the UK here, officially it's 400/230V but our voltages are still 415/240 if you actually measure them.

In North America, 600v, 480v, 440v, 220v, and 208v is phase to phase while 347v, 277v, 254v, 127v, and 120v is phase to neutral. From what I understand, the 440v/254v systems seems to be exclusive to Mexico while 220v/127v at 60hz is used in Mexico, Brazil, and Saudi Arabia.

From what I understand in that video, 208V is 'high leg' phase to ground 

IIRC, those high leg delta systems aren't that common in newer installs. Newer installs requiring 208v seem to favour the simpler 120/208v wye system he shows after the high leg delta.  The delta system is a bit confusing in that the voltage between phase to ground the on the stinger leg is 208v while the phase to ground voltage on the other legs is 120v.

347/600v systems are pretty common here. Usually on those systems the other voltages if required would be fed from a dry type step down transformer located in the premises.

The UK system seems much easier to understand with 240v phase to ground for domestic and commercial and 415v between phases for commercial.