In high lightning areas, what conductor size is recommended for the PBB?

• A. #4/0 AWG
• B. #2 AWG
• C. #6 AWG
• D. #8 AWG

Answer: (A)

Lightning events generate very large surge currents, so the path that carries those currents must have very low impedance. The PBB serves as the main bonding/grounding point, and during a strike it needs to carry that surge current with minimal voltage rise to keep equipment bonded and protected. A larger conductor has lower resistance and higher current-carrying capability, which reduces heat buildup and the potential for voltage differences to develop across components connected to the grounding system. In high-lightning areas, you size the PBB conductor large enough to handle the surge reliably, typically using the heaviest practical standard size for this purpose, such as 4/0 AWG. Smaller conductors would raise impedance and heat under surge, increasing the risk of damage and bond breakdown.