US and EU don't use the same voltage. Can you buy the lunchbox in EU then buy for example the 512c in US and have no prblem with voltage? Or do you have to buy both from the same?
The power supply should be switchable from 240 to 120, so it doesn't matter.
On the chassis itself it only wants DC voltage and that is all the modules get. The power supply handles the conversion from 120/240VAC to +/-16VDC and 48VDC.