Does this really have anything to do with clearing a fault (operating an OC device) faster?
Lightning produces fast rise-time events on the order of a few microseconds, and the delay-line effect is in the same range. How can these affect the response time of an overcurrent device, which operates in a range of tens to hundreds of milliseconds?
I'll accept the explanation that it's to reduce the effective inductance of the wire, improving its ability to conduct fast-transient surges. After all, a wire running through a ferrous tube is topologically equivalent to a single turn through a toroidal core (a skinny, but very, very thick core).
