What is the maximum allowable gauge for the bonding jumper connection to a supplemental grounding electrode?

The maximum allowable gauge for the bonding jumper connection to a supplemental grounding electrode is 6 AWG. This requirement is established to ensure adequate conductivity and to minimize the resistance within the grounding system, thereby ensuring effective fault current return paths. The choice of 6 AWG strikes a balance between sufficient conductor size to handle potential fault currents and practical application in configurations where grounding systems are integrated.

Using a smaller gauge wire, such as 8 AWG or 10 AWG, could lead to increased resistance, potentially compromising the effectiveness of the grounding system. On the other hand, while a 4 AWG might offer greater conductivity, it exceeds the requirements for the bonding jumper in this context, along with possibly resulting in unnecessary expenses and difficulties during installation due to the heavier gauge. Thus, the selection of 6 AWG adheres to safety standards while providing reliable performance.