It would be extraordinarily unlikely, because the power grid of the US and Canada are not one thing.

Separate regional power grids all have their own management. The northeast US and Eastern Canada did have a major power outage years ago and it was managed about as well as any other major outage.

Texas has its own isolated grid and it lost power for a while when a stronger than expected winter storm hit. It was a bit of a shitshow because the state isn't set up to handle that kind of weather.

So the answer is just like any other question about the Americas - depends on which region is in charge of it, and why it happened. The US does have a federal government, but for MOST things the federal government is only in charge of supporting the states, not running them.