Power outage today, and a great opportunity to see if I wired the APC correctly. Turns I made a few tiny mistakes. The SUA1500 has only four power connectors to which I attached the NAS and the DellR710. I did not attach the Mikrotek switch, because it uses a different power adapter. I also forgot to wire the rackmount LCD screen. I do not use the graceful shutdown functionality of the SUA1500, so any shutdown has to be done by hand.
With the switch offline, I could not reach the rack from my laptop. And at the rack itself, I could not log on to the machines because the screen wasn't running. So much for careful planning. Or rather: careful planning overruled by last minute decisions, such as the decision to not connect the switch.
Fortunately, the outage only lasted a few minutes which was enough for the APC to handle. Then, I found out that I still could not reach anything because PFSense (which I thought was not necessary - why would I want to reach the internet during a power outage anyway) asks for a password for its webinterface during boot (WHY!) and got stuck there. Also, I fail to understand why I cannot reach my internal network when all switches are up but the router isn't.
Back to the drawing table!