3000va at 120volt [303b] or 208v [383b], is still 3000va... VA is volt-amps. So the 208volt just takes less amps to get that VA. You cant plug more stuff into it.
The difference is important when your consumption gets very large. 10 racks taking 3000va each at 120volt suggests 250amps (30000/120) versus 144 amps for 208.
That large of a difference in amperage effects your electrical system. Services, Panels, and Neutrals are all sized based on amperage. Your electrician will make alot of money if you keep your UPSes at 120v with any sizable load.
We recommend going to 208v if your total load is over 5000va. And if its over 30,000va then go to a 3phase UPS.
