What is the required method for sizing the grounding electrode conductor for a grounded 12,470-volt system according to the NEC?

The correct method for sizing the grounding electrode conductor for a grounded 12,470-volt system is found in Table 250.66 of the National Electrical Code (NEC). This table provides the appropriate sizing for the grounding electrode conductor based on the size of the service-entrance conductors. Specifically, it addresses the requirements for grounding conductors based on the size of the system's conductors, ensuring proper safety and efficiency in the grounding system. This is vital in high-voltage systems, where maintaining an effective grounding system is crucial for operational safety and protection against electrical faults.

The other tables referenced do not apply to the sizing of grounding electrode conductors for this type of system. For example, Table 250.62 pertains to the size of grounding conductors for grounding systems, but does not provide the specific guidance necessary for the conductors associated with a 12,470-volt service. Understanding the distinctions between these tables helps in ensuring compliance with NEC regulations and maintaining safe electrical practices.