What happens when an EMP strikes, do all electronic devices within range fail catastrophically, or only those that are plugged into the grid, in other word, is the surge generated internally by the devices or is it coming down the line.
What about devices not connected to the power grid but connected by say a TV cable, telephone wire or eternet cable.
Also, are those devices physically damaged or can they regain functionality once the pulse passes.
Is it a surge that a normal surge suppressor can protect against.
The ElectroMagnetic Pulse induces a voltage potential in any conductor perpendicular to the pulse propagation direction. The longer the conductor, the higher the voltage. This makes a voltage spike that can damage electronics. The length of conductors in your computer or radio are short enough that it probably will do very little. The length of the power lines that carry power to your toys, on the other hand, are hundreds of miles long. If your toy is plugged in, ZAP!
As far as a surge suppressor stopping it, it depends on how bad it is at that particular location. Some places get bigger zaps than others, depending on things impossible to determine accurately in advance. You might get lucky, and someone a mile down the road might not.
To address a couple of other questions specifically:
Any metal wire can create an EMP effect, so all of the lines you mention might produce an EMP. However, fiber optic lines would not create an EMP effect, since they’re not conducting electricity.
Devices may or may not be physically damaged. The power surge certainly has the potential to damage sensitive components the same way a nearby lightning strike might. However, some devices will be protected by fuses - a good surge protector is an example. If it’s just a blown fuse, you can simply reset the device or replace the fuse and get it working again. If the circuit board is melted, you’ll have a much bigger challenge.