I'm relocating my office to the basement and where I want the PC places it between the two possible power outlets, roughly 20 feet away. My battery backup units power cables won't reach that far ...

It has probably happened to you if you've ever owned a desktop LCD or desktop tower: the curse of the not-quite-long-enough extension cable. It's pretty difficult to move a whole desk once you've ...

UPS->splitter->wall isn't. edit: in theory, a 15-amp cable would be fine, since no single device in the US is allowed to pull more than 15A from the wall. But get a 20A anyway, just to be safe.