Should the bare copper cable of a lightning protection system be run through the building and attached directly to the wood framing?
Cable conductors for a lightning protection system may be run anywhere either exposed or concealed within the building construction. We think of large electrical conductors as being sized to allow for heating, but having the wires exposed to constant electrical load causes the heat. A lightning protection system is a passive grounding system. It will provide a path for the lightning when necessary, but only for that short duration when the strike attaches. Since lightning travels at such a high rate of speed, there is no heat generated on the conductors of a lightning protection system, as long as it is part of a continuous path into the grounding system. In many cases the cables are run exposed on wood framing members, or even routed through the framing to conceal them within wall spaces behind the sheetrock. The grounded conductors will be exposed to lightning for nanoseconds at most, with no damage to the structure.
