Here in Florida we have a lot of thunder storms and when on pulls up the voltage it will take the surge protector frying the surge protector. When I have opened the surge protector the wire is fried. I had on on a fitness bicycle and it when though the surge protector and fried the electronics of the fitness bicycle.
This is an example of what can happen in an EMP attack but the amplification can be 1,000 times higher or more. Some wire will fry and some may burn the plastic covering but not the copper wire.
I had a lighting storm hit a house on a beach where it hit the meter outside the house and the wire inside the meter all melted down and the triped many of the breakers inside the house, fried three surge protectors where one started a small fire, luck I had rented the house for a week and the renters turn off the fire.
Can you see what a total EMP attack can do!