What must the PV system disconnecting means plainly indicate?

The correct choice highlights the importance of clarity regarding the operational status of the photovoltaic (PV) system disconnecting means. It is crucial that the disconnecting means clearly indicates whether it is in an open (off) or closed (on) position. This visibility is vital for safety, as it allows personnel to quickly discern if they can safely work on the system or if it remains energized.

Providing a clear indication of the open or closed position ensures that anyone interacting with the system can make informed decisions, reducing the risk of accidental electrocution or equipment damage during maintenance or emergency situations. Markings or indicators should be prominent and easily understandable to all users to uphold safety in accordance with the National Electrical Code (NEC) regulations pertaining to renewable energy systems.

Other aspects such as voltage rating, weather resistance, or installation date, while important for various reasons, do not directly affect the immediate operational safety regarding the status of the disconnecting means.