250.4 clearly states that electrical systems that are grounded shall be connected to earth in a manner that will limit the voltage imposed by lightning...
It then goes on to talk about grounding and bonding of electrical equipment and other conductive materials that are "likely to become energized".
At what point are the grounding and bonding requirements required to deal with lightning protection and not just ground faults within the electrical system?? For example, would a metal chimney extending up above the highest point of the structure require bonding?? Why or why not?? If so, how do you determine the size of the bonding conductor? Let's say the metal fireplace has a fan. #14 AWG circuit with equipment ground. Is that sufficient to withstand a lightning strike?
Just curious how others view the wording of 250.