Electrician's Licensing Practice Exam

The correct choice for the sizing of grounding electrode conductors is indeed found in NEC 250.66. This table specifically outlines the appropriate sizes for grounding electrode conductors based on the size of the largest ungrounded conductor. Grounding electrode conductors are vital for ensuring safe electrical systems, as they provide a path for fault currents and help maintain the safety and reliability of electrical installations.

The table accounts for different conductor types and their respective sizes to ensure adequate protection. By following the guidelines in NEC 250.66, electricians can determine the appropriate size for grounding electrode conductors relative to the system in place, helping to prevent issues such as ground faults or equipment damage.

Other options mentioned refer to different topics within the NEC:

- NEC 250.65 deals with the requirements for ground rods and different grounding methods.

- NEC 300.5 covers the burial depth of conductors.

- NEC 310.15 addresses the ampacity of conductors. Each of these sections serves a different function within electrical installations and does not pertain specifically to grounding electrode conductor sizing.