Which voltage and phase arrangement requires ground-fault protection of equipment for each service disconnecting means rated at 1,000 amperes or greater?

The requirement for ground-fault protection of equipment for services rated at 1,000 amperes or greater is specifically stipulated for certain voltage and phase arrangements in electrical systems. The configuration that requires such protection is the 480Y/277V, 3-phase, 4-wire, wye-connected system.

This system is a wye configuration, which provides a neutral point that is grounded. This grounding, along with the voltage level and phase characteristics, is critical in industrial and commercial settings where high power levels are involved. The presence of a grounding conductor helps to maintain safety and protects equipment by detecting ground faults and minimizing the risk of electrical shock or fire due to faults.

In contrast, the other configurations listed do not require ground-fault protection of equipment in the same manner. For example, the single-phase arrangement and delta-connected configurations either have different grounding schemes or voltage levels that do not necessitate the same level of ground-fault monitoring. Thus, the specific electrical characteristics of the 480Y/277V, 3-phase, 4-wire, wye-connected system align with safety protocols in electrical installations.