Backup power...
I was told a story (yes, second hand) about a power failure at a telephone central office. So, the power failed one day. Well the central office has batteries that take over in such cases, but they don't last too long. So, there is a nice gas (natural) powered turbine to generate power for the "duration" of the power failure. This is a "goodf thing:. So to start said turbine, it has a nice large air tank to spin the beast up. Super easy, So the chief flips the switch to start the turbine up, and it does nicely. Now to switch it over to power the "plant". Well, over the course of time lots of things have been plugged in and while the power company could nicely handle the load, the gas turbine generator could not. So, the whole thing failed, and they were back to square one. Not to worry, the air start system had enough to do two starts (gotta love the capacity). Do, another start, and a wise man would re-supply the air start system BEFORE switching the power over. Nope, he just flipped the switch and the same failure happened. Well, with only two starts available, they had to sit and watch as the central office died around him. A big lesson learned the hard hard hard way.
I wasn't informed if procedures were changed, but I suspect so!