What is the minimum size for the grounded (neutral) conductor of a separately derived system when there is no load?

The minimum size for the grounded (neutral) conductor of a separately derived system, particularly when there is no load, is determined by specific code references. The correct choice refers to Table 250.102(C)(1). This table provides guidance on the sizing of the grounded conductor based on the size of the largest ungrounded conductor in the system.

When sizing grounded conductors, it is essential to use appropriate tables and consider any applicable local codes or amendments. Table 250.102(C)(1) specifically addresses the minimum size for grounded conductors in separately derived systems, ensuring that the neutral conductor is adequately sized to handle potential fault currents and to adequately support the system under any conditions, even with no load present.

In contrast, Table 250.66 primarily deals with grounding electrode conductors and their sizing concerning the size of the grounding electrode, while specific conductor sizes, such as 2 AWG or 4/0 AWG, would not correctly reflect the requirement set out for the grounded conductor in this context. Therefore, the correct reference to Table 250.102(C)(1) aligns directly with the necessary sizing protocols for a separately derived system's grounded conductor.