What size should the single object above-ground external grounding conductor be?

• A. #4 AWG copper jacketed
• B. #6 AWG copper jacketed
• C. #8 AWG copper jacketed
• D. #10 AWG copper jacketed

Answer: (B)

The key point is choosing an external grounding path that stays safe and reliable in outdoor conditions. An above-ground external grounding conductor must provide a low-impedance path for fault currents and lightning energy to reach the earth, while also withstanding weather and physical wear. For a single external grounding object, #6 AWG copper jacketed is the appropriate minimum because it offers a solid conductor cross-section to carry fault current reliably and the jacket protects the conductor from moisture, corrosion, and damage outdoors.

Smaller sizes like #8 or #10 may not handle fault or transient currents well in an outdoor environment, and while larger sizes like #4 would still work, they’re typically unnecessary for a single-object external ground and would add unnecessary cost and stiffness.