Remins me of an incident at work a few years ago. They used to test the UPS once a month, cutover Friday morning and run until Saturday off the generator. One month they did this and about a week later the power really went out. UPS ran about half an hour and quit. Of course the data center staff was running around pushing buttons and such trying to get it restarted, but the generator engine would only crank. When someone came in to inspect it, turned out after the test the week before no one had remembered to have the diesel tank refilled and it had run out of fuel... That was certainly on the "fix" list for the power supply.