[ghshephard]

You seem to know a lot about this, so all I can do is reiterate that when we take our electronics to florida to be tested, our QA guys make it clear that no company's electronics are designed to survive a lightning strike - including ours. (Though we are designed to resist a 22 calibre bullet). We install a lot of lightning arrestors, mandatory in Florida, São Paulo, Singapore -- and we seem to do fine in those areas (knock on wood) - but I've been told that's to prevent a nearby lightning strike from running down the antenna line into our electronics. If our RF gear (which is mounted outdoors in weather rated containers) gets hit with a direct strike - 100% guaranteed destruction.

[eigenvector]

I think you and GP are actually agreeing. The goal of a lightning protection system is to ensure that when a structure (antenna, wind turbine, transmission tower, etc.) is hit by lightning, the lightning energy is provided with a low impedance path to earth such that any sensitive equipment inside or attached to the structure is not exposed to currents and voltages beyond its design limits.

There are other considerations as well for personnel safety, like ensuring that the ensuing ground potential rise doesn't expose someone standing near the earthing point to a shock hazard.

Going back to the original comment, lightning protection in wind turbines is more or less a solved problem. Direct hits on blades are routine and any utility-class wind turbine will be designed with an appropriate system for the area in which it is located. Now, when your turbine is on a big rock, that's a problem and you may have to blast and backfill to achieve a sufficiently low earth resistance.

[classicsnoot]

From all i have read, direct strikes on gear is a grab bag of destruction. I've read that in the Vietnam Conflict guys would get shot and the bullets would bounce off of their skin [strange effect of velocity, turbulence, and chance], so i bet there are examples of "look mom, no destruction" but i tend to side with you, at least as the guy managing this project: at no point am i going to say "cannot fail", "works everytime" or any version of the two. If you have never been to Maine, it is beautiful. If you have never built in Maine, don't get attached. The sea wind destroys everything. I kept my tools covered every day on a 42 day stint except 1, and the rust is ubiquitous. So i build to fail. The real question is, how long can i draw out the failure?