For one- or two-family dwellings, the primary protector bonding conductor or grounding electrode conductor must generally not exceed how many feet in length?

• A. 10 feet
• B. 15 feet
• C. 25 feet
• D. 20 feet

Answer: (D)

The key idea is keeping the bonding path for protective devices deliberately low in impedance. For one- or two-family dwellings, the primary protector bonding conductor must be kept short so surge energy has a quick, low-resistance path to the grounding system. Limiting this conductor to 20 feet helps ensure the surge protection device can clamp effectively and that metal parts don’t develop dangerous or unbalanced voltages due to extra impedance along the path. A longer run would add impedance, potentially delaying fault clearance and reducing protection performance. Hence, the maximum allowed length is 20 feet.