Supplementary Bonding Network/Grid uses what gauge? Can flat be used?

• A. Minimum #6 AWG for round conductor; flat can also be used
• B. Minimum #4 AWG for round conductor; flat cannot be used
• C. Minimum #8 AWG for round conductor; flat can be used only outdoors
• D. Minimum #2 AWG for round conductor; flat can be used anywhere

Answer: (A)

The main idea here is how the supplementary bonding network/grid is sized and what shapes of conductor are permitted for equipotential bonding. This network provides a low-impedance path to tie together all metal parts so they sit at the same electrical potential, which helps prevent harmful potential differences during faults or transients. Because it must carry bonding current safely and not overheat, the conductor size is prescribed.

The correct approach is to use a minimum six gauge copper for a round conductor, and a flat conductor is also allowable as long as it provides the same electrical capacity and is installed with proper fittings and termination for bonding service. Flat straps are commonly used when routing space is tight or when a flat profile is preferred, but they must be rated for bonding and meet the same cross-sectional area (capacity) as the minimum round conductor to ensure adequate current-carrying capability.

The other options either suggest an incorrect minimum size or forbid using flat conductors, which doesn’t align with standard practice where conductor shape is flexible as long as the electrical requirements are met.