The Siemens 5SM1930-0 is a stationary leakage current measurement unit designed for Type A residual current detection. It is rated 63 A, 4-pole, with a fixed measuring range of 0-300 mA — meaning it continuously monitors for sinusoidal AC and pulsating DC fault currents down to 0.3 A, based on a residual current protection device architecture. There is no alarm output on this unit; it reports status through the upstream RCD or monitoring system rather than a local dry contact.
Mounts as a stationary measuring device in the panel — no external current transformer is required, which saves DIN-rail space and reduces wiring. The 4-pole design covers three-phase plus neutral, typical for a 63 A feeder in a distribution board or machine supply. Because it has no alarm output, integration relies on the upstream RCD or PLC to pick up the trip signal from the residual current path.