The thing about lightning rods is you must present the lowest impedance path to an effective ground. A truly lightning rod system would use similar gauge rods on insulated standoffs down the side of the structure and a deeply driven section of larger rod to earth. I visited a historic inn which was a few hundred years old and for some reason has a very high frequency of lightning strikes. The entire collection of inn structures is topped with multiple pointed spikes with multiple smaller stalks with more spikes. The spikes are all on a huge bus bar that is held off the roof with glass insulators and this practice is carried down the side of the all of the inn's structures and into a collection of iron rods all mechanically clamped to the main rod from the structure roofs. These grounding rods are hammered into the earth several feet and inspected annually. They seem to take it very seriously, it works as far as I can tell because we were there in a summer lightning storm and they called us all in from the grounds as the lightning storm hit. You can feel it in the air on your skin!?
But as Michael suggested it is far safer to have an effective lightning rod some distance from the structures being protected to minimize the impact on the structure wiring and electronics. It must be significantly taller than surrounding structures to be effective.?
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Chip Louie - Chief Daydreamer Imagination Hardware
Chip Louie