Nothing would happen to the electrical infrastructure outside of fifty miles of the blast radius. It might take a couple of days for the grid to be back to normal, but sh*t happens all the time and the world does not end.
And why were several of the US nuclear tests to determine how to best achieve EMP? And remember, those were tube days, not even transistors, and certainly not microcircuits.
I'm not smarter than everyone else, and honestly, I could give a rat's pointy little tail, because I can live comfortably in a mid 1800s environment (did it in the mountains for 2 years).
/johnny
And we are much more vulnerable now than we were 50 years ago.
/johnny