What this part is and what it does
The Siemens 3RH1911-1GA04-ZX95 is a SIRIUS auxiliary switch block with 4 NC contacts, designed for snap-on mounting onto contactor relays and power contactors. It uses screw-type terminals for the auxiliary and control current circuits. Rated for a maximum of 10 A, with specific current ratings across voltages: 10 A at 24 V, 6 A at 24 V, 125 V, 230 V, and 250 V; 4.7 A at 60 V; 3 A at 400 V; and lower ratings at higher voltages up to 600 V. The contact reliability is rated at one incorrect switching operation per 100 million operations at 17 V, 5 mA.
Panel integration and mounting
The block snaps onto a contactor relay or power contactor. Dimensions are 36.5 mm wide, 37.5 mm high, and 41.5 mm deep. The front has IP20 protection, so it's suited for enclosed control panels where no washdown or outdoor exposure occurs. The screw terminals accept 2x (0.5... 1.5 mm²) or 2x (0.75... 2.5 mm²) with core end processing, or 2x (20... 16) or 2x (18... 14) AWG. Operating temperature range is -25 to +60 °C; storage range is -55 to +80 °C.
What the ratings mean for fit
The 10 A maximum rating at AC-15 duty governs switching of solenoid loads like contactor coils — the typical application for an auxiliary block. The 4 NC configuration follows EN 50011, providing normally-closed feedback for safety circuits or status monitoring. The 6 kV surge voltage resistance and 690 V insulation voltage at pollution degree 3 mean this block is rated for industrial environments with moderate contamination, not just clean office panels.