Which marking method is acceptable for the grounding conductor on a ground-type receptacle?

The acceptable marking method for the grounding conductor on a ground-type receptacle is indicated by the specific type of hardware used, which is the hexagonal head screw or nut. This choice aligns with industry standards for grounding connections.

Using a hexagonal head screw or nut signals a reliable and robust connection point for grounding conductors. This method ensures that the grounding conductor can be securely attached and provides clear identification of the grounding connection point. Robust hardware is essential for maintaining the integrity of the grounding system, which is vital for safety and effective operation of electrical equipment.

The other options, although they may seem usable, do not fulfill the same requirements for strength and reliability in marking the grounding conductor. For instance, colored terminals may not provide the necessary indication specifically required for grounding connections, and round head screws or nuts may not be as easily identifiable or secure as hexagonal ones in this application. The industry standard emphasizes the significance of both the method and the material used in grounding to ensure consistency and safety in installations.