Firefighter switch with arc fault detection

The term firefighter switch indicates a remotely controllable DC Disconnect with which the DC side of a photovoltaic system in proximity of the modules (or directly below the cable outlet) can be disconnected. The disconnection of DC lines within a building ensures maximum safety for persons.

The integral arc fault detection with UL 1699B approval allows detection of hazardous DC arc faults in the PV system and immediately trips the DC Disconnect by means of the low voltage trip module. Disconnection of the circuit helps to extinguish serial arc faults already before any safety-critical situations can arise. DC arc faults can be caused by defective components such as connectors, cables, PV modules and junction boxes due to ageing, animal bite, heavy snowfall or mounting and installation errors. The integral arc fault detector now allows realization of fire prevention in photovoltaic systems.

Remote disconnection and reconnection provide ease of reset and thus high system availability even in large roof-mounted solar installations.

In normal operating condition, the system will automatically re-start after an inadvertent shutdown, e.g. due to a brief supply voltage dip.

The E-T-A technology of arc fault detection significantly enhances the safety of photovoltaic systems.