NEC Article 690 requires labels at seven key locations on a solar PV system: service equipment (690. 12 (D) (2)), all DC conduit and raceways (690. 31 (G) (4), every 10 feet), junction boxes and combiner boxes, DC. In solar photovoltaic (PV) systems, proper identification of electrical cables and conduits is essential for ensuring safety, maintenance efficiency, and regulatory compliance. As solar installations become larger and more complex, organized labeling systems help installers, operators, and. Solar PV labeling requirements are the mandatory markings, placards, and directories that NEC Article 690 Part VI requires on every permitted solar installation. In addition to safety markings, this primarily includes the clear labeling of strings, inverters, distributors and other components. These solar inverter labels and.