What is the grounding requirement for 3-phase, 4-wire systems in the wye configuration?

In a 3-phase, 4-wire wye configuration, grounding requirements are essential for system safety and stability. Specifically, the requirement to ground the neutral conductor is crucial because it provides a reference point for the system voltage and enhances the safety of both the system and personnel. Grounding the neutral helps in fault conditions by providing a low-impedance path back to ground, which can facilitate the operation of protective devices, such as circuit breakers and fuses, to clear faults promptly.

Furthermore, grounding the neutral conductor in this type of system ensures that any unbalanced loads do not lead to elevated voltages that could pose a risk of shock or equipment damage. It also helps to control transient voltages and reduces the risk of electrical fires.

The other options do not align with the grounding practices stipulated in electrical standards and codes, as they either misrepresent the requirements or are too restrictive concerning building types and voltage levels. Thus, grounding the neutral conductor is indeed the correct and necessary practice in 3-phase, 4-wire wye systems.