What is the minimum size grounded conductor required for a service where the largest ungrounded service conductor is 750 kcmil copper?

To determine the minimum size grounded conductor required for a service where the largest ungrounded service conductor is 750 kcmil copper, one must refer to the applicable electrical codes, specifically the National Electrical Code (NEC).

According to NEC Table 250.102(C), the size of the grounded conductor is based on the size of the ungrounded conductors. For copper conductors, when the largest ungrounded conductor is 750 kcmil, the code dictates that the minimum size grounded conductor must be at least 2/0 AWG. This size is calculated to ensure there is enough capacity in the grounded conductor to handle any fault currents safely and effectively.

The significance of size selection lies in maintaining safety and ensuring electromagnetic compatibility within the electrical system. Thus, 2/0 AWG is appropriate for this application, fulfilling the requirements laid out in the electrical code for such capacities.