Use 277 at 120/277 x 15 A ~ 6.5 A and 5% drop
get a 1.5 or 2 kva 277/120 UPS
the output will be regulated to 120 on a 160-280 input
2 birds with 1 stone
lower current ie Vdrop and UPS protection
example http://stevenengineering.com/Tech_Support/PDFs/41UPS.pdf
14 will do it 4.5%
use 12 and call it a day
get a 1.5 or 2 kva 277/120 UPS
the output will be regulated to 120 on a 160-280 input
2 birds with 1 stone
lower current ie Vdrop and UPS protection
example http://stevenengineering.com/Tech_Support/PDFs/41UPS.pdf
14 will do it 4.5%
use 12 and call it a day