For PV systems that are not solidly grounded, what is permitted to be the only connection to ground for the system?

In photovoltaic (PV) systems that are not solidly grounded, the equipment grounding conductor serves as the appropriate connection to ground for the system. This is crucial because the equipment grounding conductor is specifically designed to ensure that metal enclosures and exposed conductive parts are effectively grounded, thereby providing a safe path for fault currents and preventing electric shock hazards.

The equipment grounding conductor is essential in ungrounded or impedance-grounded systems, where it helps maintain safety without introducing significant ground fault current. By ensuring that the equipment grounding conductor is the only connection to ground in such systems, the risks associated with ground faults and equipment failures are minimized while making sure that personnel working on or near the PV systems remain safe.

In contrast, other connections to ground listed in the options, such as the grounding electrode conductor or the system's neutral conductor, do not fulfill the same safety purposes in the context of an ungrounded system. The grounding electrode conductor is typically used to connect the grounding system to the grounding electrodes and is not meant to carry fault currents, while the neutral conductor is involved in carrying operational current and is generally grounded in solidly grounded systems to provide a reference point. The DC disconnect switch, while crucial for the operation of PV systems, does not provide a direct ground