Four fire engines and around 25 firefighters tackled a fire at a school building on Camden Road in Carshalton.
Four solar panels on the flat roof of the building were destroyed and part of the flat roof was damaged by the fire. There were no reports of any injuries.
The fire is believed to have been accidental and caused by an electrical fault within a cable connected to solar panels.
A spokesperson for the London Fire Brigade said: "Firefighters used one of the Brigade's 32-metre turntable ladders to deploy PV Stop on to solar panels on the roof of the property."
Incidents involving solar panels are especially dangerous as it’s difficult to isolate the electrical current they generate if they are damaged or involved in a fire. When tackling fire involving solar panels, crews run the risk of receiving electric shocks as the current can travel down water jets and hoses.
PVStop works by blocking the sunlight that powers solar panels, so the process of converting light into electricity is stopped. The panels are then de-energised and the risk of electrocution is greatly reduced so crews can get closer and prevent fire spreading from a roof to the rest of the building.”
The Brigade was called at 1453 and the incident was over for firefighters at 1757. Firefighters from Mitcham, Croydon and Wimbledon fire stations attended the scene.