Safety lighting can be executed in permanent operation or stand-by operation.
In permanent operation, safety luminaires are fed from the general lighting network and, in case of a failure or interruption thereof, from the emergency power supply. Upon return of the general power supply, the changeover back to it must occur automatically. In permanent operation, there are two different modes:
In changeover operation, safety luminaires are only connected to the emergency power supply in the case of mains failure; otherwise they are fed by the general network.
In parallel stand-by operation, safety luminaires are continuously connected to the emergency power supply.
In stand-by operation, safety luminaires are not switched on during normal operation. They are only powered on upon mains failure or interruption. Once voltage returns, the safety lighting must switch back off automatically. In rooms where stand-by operation is provided, luminaires for general lighting must be distributed to at least two circuits.
Mains monitoring, except for individual battery systems, is implemented at the multiplier in case of permanent operation, and at the subdistributor for stand-by operation.