The new version of this section allows running PV source or output circuits (including for off-grid installations) inside a building or structure before being terminated at an accessible disconnect—as long as they are in metal raceways, metal enclosures, or metal-clad cable that complies with 250.118(10). However, there are now additional installation requirements:
Beneath roofs. Wiring shall not be installed within 25 cm (10 in.) of the roof decking or sheathing except where directly below the roof surface covered by PV modules and associated equipment. Circuits shall be run perpendicular to the roof penetration point to supports a minimum of 25 cm (10 in.) below the roof decking. The 10-inch requirement is to prevent accidental damage from saws used by firefighters for roof ventilation during a structure fire.
Flexible wiring methods. Where flexible metal conduit (FMC) smaller than metric designator 21 (trade size 3/4-in.) or Type MC cable smaller than 25 mm (1 in.) in diameter containing PV power circuit conductors is installed across ceilings or floor joists, the raceway or cable shall be protected by substantial guard strips that are at least as high as the raceway or cable. Where run exposed, other than within 1.8 m (6 ft.) of their connection to equipment, these wiring methods shall closely follow the building surface or be protected from physical damage by an approved means.
Marking or labeling required. The following wiring methods and enclosures that contain PV power source conductors shall be marked with the wording “Photovoltaic Power Source” using permanently affixed labels or other approved permanent marking: Exposed raceways, cable trays, and other wiring methods; covers; or enclosures of pull boxes and junction boxes; and conduit bodies in which any of the available conduit openings are unused.
Marking and labeling methods and locations. The labels or markings shall be visible after installation. Photovoltaic power circuit labels shall appear on every section of the wiring system that is separated by enclosures, walls, partitions, ceilings, or floors. Spacing between labels or markings, or between a label and a marking, shall not be more than 3 m (10 ft). Labels required by this section shall be suitable for the environment where they are installed.
