What is the minimum size for the grounded conductor when there is no load on it in a separately derived system?

The minimum size for the grounded conductor in a separately derived system is determined by the requirements specified in Table 250.102(C)(1). This table outlines the minimum size of grounding conductors based on the size of the service-entrance conductors or the overcurrent protection device rating. It ensures that the grounded conductor is adequate to handle potential fault currents and provides a safe pathway for electrical faults.

The distinction of being based on values in this table emphasizes the importance of proper sizing according to established electrical codes and safety standards. It ensures that the grounding system can effectively manage excess current during a fault, ultimately protecting both the electrical system and individuals.

The other options do not specifically address the requirements for sizing the grounded conductor in the context of a separately derived system. For instance, citing the overall rating of the panel may not consider factors that specifically pertain to the grounded conductor, while stating a size of at least 6 AWG copper does not align with the varying requirements depending on conductor sizes outlined in the relevant tables. The notion of equating it to the size of the service entrance conductors lacks the specificity and context necessary for proper adherence to electrical code requirements.