A fireman's switch is a specialized switch that allows firefighters to quickly disconnect power from high voltage devices that may pose a danger in the event of an emergency.[1] According to the Institution of Electrical Engineers, any electrical device operating at over 1,000 Volts AC or 1,500 volts DC, must be equipped with the switch.
DC isolator is integrated into the solar inverters, but even when the DC isolator is turned off, there will still be up to 600~1500Vdc between the inverter and the PV panels.
As long as there is radiation on the panel, a voltage of 600~1500Vdc will be generated on the DC side. If fire happens in installation without firefighter safety switch, the high voltage DC current inside the panel array or between the panel array and the inverter will threaten the personal safety of firefighters. On the other hand, most of the circuits of photovoltaic plants used 600 ~ 1000V (some even up to 1500V) DC circuit. In an actual power station, DC arcs can be caused by fault such as poor connection, poor contact quality, insulation aging, and damp insulation, etc. Photovoltaic modules continuous generate electricity when a DC fault occurs. The DC current does not have a zero-crossing, so the fault current at the trigger location will persist for a long time and further cause a fire, firefighters may be exposed to very serious potential hazards.
Based on the market demand, Aswichhas successively launched series of firefighter safety switches of String level ERS and panel level ERP.
Protect your PV system with Aswich fireman's switch
If the temperature exceeds +70°C or if there is a failure in the AC grid for more than 5 seconds, the PEFS fireman's switchwill automatically disconnect the DC current between the PV system and the inverter.
This creates a safer environment for the firefighters and reduces potential damage to the PV system.
If the switch disconnects due to AC grid failure, it will automatically switch back on when the AC is back. The client doesn’t need to reset it manually each time.
Aswich's ERS series fireman's switch offers maximum safety to firefighters where solar PV systems are installed.works by disconnecting the PV panels from the rest of the system as soon as the main AC breaker is tripped or switched by the firefighters. This is achieved by the inherent under voltage release which automatically disengages the ERS when the AC voltage is not present. its maximum loop voltage can be up to 1500V which meets the requirements of high-power panel.
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