Hey, someone who understands electricity here. Long cables can pick up very high voltages by coupling to a strong electric field; 50kV per square meter obviously induces more current in the conductor proportional to how many meters the cable run is.

The insulation of the cable itself can suffer dielectric breakdown and short against other conductors given a high enough voltage (higher than EMP, IIRC), but the real risk is the stuff attached to the cable, which would receive significant induced currents through the cable. The E1 component of the EMP is too fast for overcurrent protection devices to trip, so there would be damage.

The sensitive chips in the early computers are even more sensitive and far more numerous now. A CPU is nothing but.

Devices without mains connections and with short conductors are less likely to suffer damage than longer ones or those connected to the grid.

*Some* things would survive, but *enough* would fry to knock out most of civilization for months.