What is the minimum size grounding electrode conductor required for a building served by a 400-ampere feeder?

The minimum size grounding electrode conductor required for a building served by a 400-ampere feeder is based on the guidelines established in the National Electrical Code (NEC). For a 400-ampere feeder using copper, the NEC specifications dictate that the appropriate minimum conductor size is 1/0 AWG.

This size is determined considering the ampacity requirements and the need for grounding conductors to effectively handle fault currents, ensuring safety and protection of personnel and equipment. The grounding electrode conductor connects the ground rods or other grounding systems to the electrical grounding system of the building, playing a crucial role in system reliability and safety.

Other sizes like 2/0 AWG, 1 AWG, and 3 AWG exceed the requirement but are not the minimum specified size for the application described. Understanding these standards helps ensure compliance with electrical safety regulations and the efficient operation of electrical systems.