Lightning protection in these types of cables is well understood, since the telephone system contended with the same problem. Fortunately EMP effects are mostly

Lightning protection in these types of cables is well understood, since the telephone system contended with the same problem. Fortunately EMP effects are mostly accounted for by lightning protection, when it comes to the outside plant. There are definitely lightning arrestors where cables enter facilities, but I would wager the facilities were built with halo grounds. There is integral EMP shielding in the design of the bunkers, as well, with a steel liner surrounding the concrete.