In most PV systems, DC isolation switches are integrated into the PV inverters. But even when the DC switch is turned off, there will still be up to 600~1500VDC between the inverter and the PV panels. In case of fire, firefighters may be exposed to very serious potential hazards.

But if firefighters shut down the AC before putting out the fire, the PEFS series firefighter safety switch will detect the grid failure, and after 5 seconds, the PEFS will automatically turn off the isolation switch. Because this safety switch is mounted close to the PV panel, the DC within the building is disconnected, which creates a safe environment for firefighters, reduces the potential damage, and ensures the safety of the PV system.