“Most telecommunications facilities have at least eight-hour backup often required by regulation—but locations prone to lengthy power outages, such as hurricane-prone areas, require backup capability between 24 and 72 hours.”
https://www.nrel.gov/docs/fy09osti/44520.pdf
Righto. But also see my post 24: Info. from my EE buddy in Switzerland. There could be some problems, interestingly enough, perhaps mostly in the most developed Euro countries.
(I try to follow my own philosophy that posters willing to accept solid info. not fitting their own predefined ideas make the best members of a forum. I come here a lot more to sift through information and learn than to comment, tho’ it might not seem that way to some, and though I know biases are very strong here.)