Yes, just one circuit. and one outlet in the bedroom and one in the living room. This is an old building so I have to live it. Panel size I am not sure. I know it was switched over at some point from screw-in fuses to breakers. I am going to assume these are decades old.
Gocha. Well, I can only say, continue to be wary of putting in a full sized dust collector in there. Might not be worth the risks. Do you have room for an overhead air filter? Or even a decent shelf or something you could put one on? I have one of those, and it does a lot to suck up a lot of the small dust.
It is not as good as a proper dust collector, and a full size DC with proper ducting is next on my list, and I've put a lot of effort into figuring out what would be necessary for it to be useful... Key thing I've discovered is you usually need a fairly good sized unit even for a small shop, to really suck up all the FINE dust. Apparently (to my surprise) sucking up the chips and larger scale dust is actually easier than sucking up all the fine dust...fine dust is where things get more complex and costly.
I'll offer that, so far, I'm doing pretty well with a Fein shop vac, a simple bucket based vortex system, and some 4" ducting. It gets most of it. The vac is around 8 amps or so. Not too bad, but...again, if you really have just one circuit, and are also running other power tools... Even that 8 amps might be too much. I have separate circuits in a subpanel I installed in my workshop for the overhead air filter, shop vac, and lathe. I also have separate circuits for my mitersaw/bandsaw, and I have a second lathe also on its own circuit. So, when I'm running all these things together, each one, basically, is on its own breaker...