What is the minimum size of the grounding electrode conductor for a building supplied by a feeder?

The minimum size of the grounding electrode conductor for a building supplied by a feeder is specified in the National Electrical Code (NEC). The correct response references Section 250.66 of the NEC, which provides guidelines on the size of grounding electrode conductors based on the size of the largest ungrounded service-entrance conductors. This section is crucial for ensuring that the grounding system can safely handle fault currents and effectively protect both equipment and life.

Grounding electrode conductors must be adequately sized to ensure a low-resistance path back to the earth for fault currents, which helps in the proper operation of overcurrent devices and minimizes the risk of electrical shock or fire. The NEC designates specific minimum sizes for different types of conductors, and Section 250.66 clearly addresses those requirements, particularly for buildings supplied with feeders.

In contrast, the other choices reference sections of the NEC that either pertain to different aspects of grounding or do not specifically address the minimum size requirements for grounding electrode conductors as it relates to feeders. Thus, the correct answer aligns with the established electrical safety standards that ensure effective grounding practices.