Oklahoma Electrical Practice Exam

What is the smallest size copper wire allowed as the sole connection to a concrete encased electrode for a 350 kcmil copper service entrance wire?

1. #4 AWG

2. #3 AWG

3. #2 AWG

4. #1 AWG

The correct answer is: #2 AWG

The smallest size copper wire allowed as the sole connection to a concrete encased electrode for a 350 kcmil copper service entrance wire is #2 AWG. This requirement is established to ensure that the grounding conductor is adequately sized to handle potential fault currents, providing effective grounding and ensuring safety. In grounding systems, especially with substantial service entrance conductors like a 350 kcmil wire, the grounding electrode conductor must be appropriately sized to ensure that it can carry the maximum possible fault current without overheating or becoming a safety hazard. The National Electrical Code (NEC) specifies minimum sizes for grounding conductors based on the size of the service entrance conductors. For a service entrance conductor size of 350 kcmil, #2 AWG is the minimum acceptable size for the grounding connection to a concrete encased electrode, facilitating proper performance in fault conditions. This ensures not only sufficient conductivity but also compliance with safety standards for electrical installations.