Equipment grounding conductors installed with medium-voltage cables are generally required to be sized based on what minimum size for copper?

The minimum size for copper equipment grounding conductors that are installed with medium-voltage cables is 6 AWG. This sizing requirement is essential for ensuring that the equipment grounding conductor can adequately handle fault currents, provide a low-impedance path for electrical faults, and ensure the safety and reliability of the electrical system.

Using a 6 AWG grounding conductor fulfills the necessary reliability standards while minimizing the risk of ground faults that could lead to equipment damage or pose safety hazards. Sizing the equipment grounding conductor correctly is particularly critical in installations involving medium-voltage cables due to the higher voltage and potential fault current levels, ensuring that the system is protected under fault conditions.

In the context of other sizing options, sizes smaller than 6 AWG, such as 8 AWG, 10 AWG, or 4 AWG, do not meet the requirements necessary for medium-voltage applications. An undersized conductor might not safely carry fault currents, which increases the risk of failure in the grounding system. Hence, the choice of 6 AWG is the appropriate and required standard for ensuring a safe and effective grounding method in this context.