Which wiring methods containing photovoltaic power source conductors must be marked PHOTOVOLTAIC POWER SOURCE?

The correct choice highlights the requirement that exposed raceways and cable trays containing photovoltaic power source conductors must be marked with "PHOTOVOLTAIC POWER SOURCE." This marking is essential for ensuring safety and proper identification of the wiring methods that carry electricity generated by solar panels, which can differ in their characteristics and hazards compared to other electrical conductors.

Exposed raceways and cable trays are often found in areas where maintenance or modifications may occur. Marking these components helps to alert workers and emergency responders to the presence of live photovoltaic conductors, significantly reducing the risk of accidental contact with these wires during installation, maintenance, or emergency situations.

By providing a clear indication of the conductors' purpose, the marking enhances the overall safety of the installation. It ensures that anyone encountering these conductors understands that they are working with a power source that has unique operational characteristics and potential hazards associated with solar energy systems. This requirement aligns with the NEC's goal of maintaining safety in electrical installations, particularly as the use of renewable energy sources becomes more prevalent.