The Siemens 3RH2911-4HA03 is a SIRIUS auxiliary switch designed for snapping onto the front of contactor relays and power contactors in sizes S00, S0, S2, and S3. It provides additional contact sets for status feedback, interlocking, or control logic without expanding the panel footprint — the 36 mm width matches the contactor's own envelope.
The switch carries a rated operational current of 10 A at AC-12 (resistive load) and 6 A at 24 V, 230 V for general use. The AC-15 rating at 690 V is 1 A — that is the inductive load capability for solenoid or contactor coils, which is the typical duty for an auxiliary in a motor starter. The mirror contact feature per IEC 60947-4-1 means the normally closed contact cannot be held closed by a welded main contact when used with a 3RT2 contactor, a requirement for safety-related feedback circuits. The 6 kV rated surge voltage resistance ensures the contacts withstand transient overvoltages common in industrial control panels without flashover.
Mounting and connection
Snap-on mounting to the contactor front — no tools needed, aligns with the contactor's own DIN-rail clip. Connection is via ring terminal lugs, which provide a vibration-resistant termination for the auxiliary and control circuits. The IP00 front protection means it is intended for enclosure installation, not open-panel washdown areas.