Michael gets an explanation from NSTAR on why his power went out Monday: A transformer blew under extreme loads:

Let me say from the outset that I could very well have my facts wrong, but from what I understand, NSTAR hasn't done the upgrade they've really needed to do on our transmission lines over the past few years. Basically, it's a large capital expenditure to upgrade everything, so instead of fixing it all at once they've simply patched it as problems arose. Needless to say, this results in a system that in the long run, costs more money to fix. ...