If a fire involves PV components, do not attempt to extinguish it until after the system is isolated. However, even an isolated system can still produce, hold and transfer energy. Underwriters Laboratories (UL) testing has shown that punctured PV components can transfer electric current to tools such as axes and saws, so be careful not to puncture solar panels or PV roofing materials during vertical ventilation operations.
When extinguishing the fire, do NOT utilize a straight stream or foam. Contain small fires with Class C extinguishing agents such as carbon dioxide or dry chemical. For larger fires where the use of Class C agents is impractical, apply copious amounts of water in a 30-degree fog pattern at 100 psi from at least 30 feet away. Avoid spreading contamination by keeping the discharge away from any nearby storm drains and bodies of water.