The minimum size of the grounding conductor for through-wall lighting assemblies is 12 AWG.

• A. 14 AWG
• B. 12 AWG
• C. 10 AWG
• D. 8 AWG

Answer: (B)

Grounding conductors are sized based on the overcurrent device protecting the circuit, per NEC 250.122. For a typical lighting circuit, the grounding conductor can be smaller, but there’s a specific installation requirement for through-wall lighting assemblies that the grounding conductor be at least 12 AWG. This larger size provides a more robust fault-path through the wall and any metal components, helping ensure the fault current can clear quickly and safely. That’s why 12 AWG is the minimum in this scenario. A smaller size, like 14 AWG, wouldn’t meet this installation rule, while larger sizes (10 or 8 AWG) would be required only if the circuit’s overcurrent protection demanded a larger grounding path.