AC voltages in the "low voltage" class vary quite a bit. I've seen nominal voltages of 208, 220-240, 277, 380-415, 460-480, 575-600, and 690 VAC. Past that I don't see anything until medium voltage and 2.2 kVAC. I have the vague idea that 575-600 VAC is common in Canada, 460-480 VAC and 220-240 VAC are common in the US, and 380-415 VAC are common the rest of the world. But that's just a vague idea, and doesn't cover 690 VAC at all.
Are there standards defining which voltage is used where or under what circumstances? Does it really vary with country or region that clearly? Is it more application-based?