What it is and what it does
The Siemens 5SM1920-8 is an RC safety socket outlet — a surface-mounted enclosure with two SCHUKO sockets, each protected by a Type A residual-current device (RCD) tripping at 30 mA. Rated for 16 A at 230 V, it serves as a local shock-protection point in industrial or commercial panels where the supply earth is already bonded but personnel need an extra layer of fault-current detection. The 30 mA trip threshold (30 000 mA in the spec field is a data-entry quirk — it is the standard 30 mA RCD sensitivity) catches line-to-earth faults before they reach a dangerous let-through energy, and Type A detection covers pulsating DC fault currents that a simple AC-only RCD would miss. That makes it suitable for circuits feeding switched-mode power supplies or variable-speed drives where residual current is not a pure sine wave.
Mounting and enclosure details
Surface-mounted, so it screws directly to a wall or panel backplane — no DIN-rail clip. The thermoplastic enclosure measures 146 mm high × 105 mm wide × 46 mm deep and carries an IP21 rating, meaning it is protected against solid objects larger than 12.5 mm (fingers) and dripping water. Not rated for washdown or outdoor exposure. The hinged lid is not transparent and is not lockable. Connection is via plug terminals; the unit has no labeling field, no integrated light source, and no overvoltage protection. Halogen-free construction is confirmed.