What size should grounding electrode conductors be for service entrances?

The correct answer is based on NEC Table 250.66, which provides the requirements for the sizing of grounding electrode conductors (GEC) based on the size of the service-entrance conductors. This table is specifically designed to ensure that the grounding system is adequate for the current-carrying capabilities of the service conductors, helping to protect both equipment and personnel from electrical faults.

Using this table, an electrician can determine the appropriate size of the grounding electrode conductor that corresponds to the size of the service conductors, ensuring compliance with the National Electrical Code. This is critical for both safety and effective operation of the electrical system.

While manufacturer specifications, the size of the service panel, and determinations by local building authorities are important considerations in the overall installation process, they do not specifically dictate the sizing of the grounding electrode conductors as effectively as NEC Table 250.66 does. Therefore, for accurate and compliant sizing of grounding electrode conductors for service entrances, referencing NEC Table 250.66 is essential.