Perfect system
All these stories make me wonder if anyone has ever had come across a good system which has stood up to multiple failures really well?
Where I used to work we had 4 RUPS which ran continuously - we ran 'off' them all the time. We could run off just 2 if pushed and routine tests where the external mains was completely disconnected were carried out and we would run on diesel for several hours just to make sure everything definitely worked.
It had not worked perfectly from day 1, but the early tests revealed several issues in design, procedures and maintenance routines.