Much, maybe all, of Mexico supplies single phase power via 2 phases from three phase power. In the US that is known in the power industry as "network power" and is usually 120/208 volts. Now 208 volts sucks. But to get 240 volts from such a configuration, you'd have to have 138.5 volts on line to neutral, and that is a bit too much for most things that want 120 volts. In Mexico they have chosen a compromise where the L-N voltage is just a little high (127 volts) and the L-L voltage is just a little low (220 volts).

electronics-lab.com

[–] myotheraccount@lemmy.world 6 points 2 days ago

Thank you

[–] criticon@lemmy.ca 13 points 2 days ago

As a Mexican I thought 127V was the norm in the West until very recently

[–] BastingChemina@slrpnk.net 3 points 2 days ago

I think it's because in a three phase system is you have 220v between two phases then you'll have 127v between one phase and the ground.

I know in France at one point before the 50s most of the country was using 110v, then some of it switched to 127v but from the 50s they decided to unify the national electrical grid to 220v. It took a while but now I don't think there is any 110v left.