Where does lightning "want" to go? I work on navigation equipment at airports, and we've had a few lightning storms recently... Every time there is lightning on (or near) the airport, we end up replacing circuit cards in our equipment. These are obviously not direct hits, because the damage would be much more evident. I understand that lightning occurs when a build up of potential (between cloud and the earth) becomes great enough to ionize the air and produce an arc to "equalize" itself. We've been having conversations about what happens when lightning hits the earth... An idea has been put forth that since our terrain is clay and is usually wet, that the lightning (or current, or energy, or whatever you want to call it) kind of travels around through the ground and might actually be using the grounding system to travel from the ground and enter the buildings housing our equipment. In other words, we're thinking that the nearby lightning is traveling through the earth, finding the copper and traveling through it and up into the building and taking out some of the circuit cards... Is this possible? One guy said that he has heard of people at other facilities (with similar terrain) who have actually disconnected their equipment from the grounding system because of this theory, and it has helped reduce damage to their equipment. It was also stated that places that have sandy soil (like Florida) don't have this problem because the lightning dissipates quicker since the loose, dry, sandy soil doesn't give a good conducting path for it to travel around in the earth and find its way to the equipment. Hence the question... Where does lightning "want" to go? Is it "satisfied" as soon as it hits the ground? One suggestion is that is it trying to "get to" the core of the earth (seems pretty unlikely to me since there would be too much insulation between the core and the earth's surface)? Disconnecting the grounding system seems like a bad idea since a direct hit would obviously turn all of our equipment into charcoal, but would it help with these transient surges that are happening when lightning strikes the vicinity? It's obviously a bit of a gamble... but the cost of replacing dozens of circuit cards over a season is quite high. If this works, the risk might pay off in the end. Especially since a direct hit would likely cause catastrophic damage anyway... Any lightning experts out there?