The tower crane IS ALREADY a "de facto" lightning rod, just as is a metal radio tower. The question to answer is "what are the assets to be protected? Operator inside enclosed cab
is safe (Faraday Cage) under most circumstances. Electrical/electronic devices require surge protection devices...
A lightning strike to rods on roof or to roof itself still may cause structural damage and/or fire. Instead of a "direct" system, an "indirect" system is suggested. Overhead grounded wires ala electric power lines or adjacent free-standing metal masts may be a better option. In either case...
