To bond the SBB to the PBB, what copper gauge is specified?

• A. #2 AWG copper
• B. #4 AWG copper
• C. #6 AWG copper
• D. Aluminum copper-clad wire

Answer: (A)

Bonding the SBB to the PBB creates a single, low-impedance path that ties the site bonding backbone to the property bonding backbone, keeping all bonded metal at the same electrical potential and allowing fault currents to clear safely. The standard calls for copper of No. 2 AWG for this bond because this size provides enough cross-sectional area to carry any potential fault current across typical bond lengths while keeping impedance low. Using a smaller gauge would raise the impedance, making the bond less effective at equalizing potential during a fault. Aluminum copper-clad wire isn’t suitable here since the requirement specifies solid copper conductors for this critical connection, which ensures durability and reliable low impedance over time.