The SITOP PSE200U selectivity module distributes the load current across several 24 V branches and reliably monitors them for overload and short circuits. It allows short-term current peaks, such as those caused by high inrush current, while branches with prolonged overload are switched off. This is ensured even on high-resistance lines and in the case of "creeping" short circuits. In such situations, circuit breakers may not trigger or may do so too late, even if the power supply could provide the necessary tripping current. The intact branches continue to receive 24 V from the SITOP supplementary module without interruption or feedback, thereby preventing a potential total failure of the system.