What is the minimum size for an equipment bonding conductor?

• A. #6 AWG or larger, each have dedicated bonding conductor
• B. #4 AWG or larger, each have dedicated bonding conductor
• C. #8 AWG or larger, each have dedicated bonding conductor
• D. #2 AWG or larger, each have dedicated bonding conductor

Answer: (A)

The key idea is that equipment bonding conductors must provide a reliable, low-impedance path to the grounding system so any fault current can return quickly and trip protective devices. For minimum sizing, copper bonding conductors must be at least #6 AWG. Using #6 or larger ensures the fault current path is capable of handling the anticipated surge without overheating or losing bonding effectiveness.

In practice, each piece of equipment should have its own dedicated bonding conductor back to the grounding bus. This isolation prevents fault currents from taking shared paths that could raise voltages on other equipment or reduce the effectiveness of the fault-clearing path if one connection were to fail.

So, the standard practice is a minimum of #6 AWG copper, with a separate bonding conductor for each piece of equipment. Larger sizes are acceptable if needed, but #6 is the baseline.