You wouldn't get much run time on a UPS with batteries that small. So, no there aren't any UPSes which fit within a junction box.

At work we have the UPSes hidden away in the room with the breaker panel. They are hardwired between the panel and the outlets which need backup power. These also use regular truck batteries, which can be connected in parallel for what ever amount of run time you want.


Pioneer PDP-5020FD, Marantz SR6011
Axiom M5HP, VP160HP, QS8
Sony PS4, surround backs
-Chris