usually the desi UPS are on a single wiring system where one wire is used for both L and N..
APC ups usually require a dual wiring system all across the house., which is a REAL PAIN IN THE ASS, and expensive
usually the Shops offer a Ground and neutral common setting inside the ups, so it can work on single wire as well.
any advice on how to do that ourselves?. and what would be the disadvantages of doing that?