Siemens 3RH2911-1FA04 SIRIUS Auxiliary Switch 4NC 690V Screw Terminal

The Siemens 3RH2911-1FA04 is a SIRIUS series auxiliary switch designed to snap onto the front of 3RT2.1 contactors and 3RH2 contactor relays. It provides 4 instantaneous NC contacts at an insulation voltage of 690 V AC, with positively driven operation and mirror contact capability for safety-critical monitoring applications. Screw-type terminals accept conductors from 0.5 to 2.5 mm².

Technical specifications:

• MLFB: 3RH2911-1FA04
• Manufacturer: Siemens
• Product line: SIRIUS
• Product type designation: 3RH29
• Contact arrangement: 4 NC instantaneous, 0 NO
• Suitability: 3RT2.1 contactors, 3RH2 contactor relays
• Insulation voltage: 690 V AC (pollution degree 3)
• Surge voltage resistance: 6 kV
• Operational current AC-15 at 690 V: 1 A
• Operational current AC-12 (max): 10 A
• Mechanical service life: 10,000,000 operating cycles
• Electrical endurance: 200,000 cycles (AC-15, 230 V)
• IP rating: IP20 (front)
• Operating temperature: -25 to +60°C
• Storage temperature: -55 to +80°C
• Mounting: Snap-on onto contactor front face
• Terminals: Screw-type
• Conductor cross-section: 0.5 to 2.5 mm² (solid, stranded, finely stranded with core end processing)
• Dimensions (WxHxD): 36 x 37.5 x 43.7 mm
• Net weight: 56 g

Features and benefits:

• Mirror contact function per IEC 60947-4-1 when paired with 3RT2 contactors
• Positively driven operation per IEC 60947-5-1 for safety relay and PLC compatibility
• 4 instantaneous NC contacts suited to interlocking, feedback, and status signaling circuits
• Contact reliability: 1 faulty switching per 100 million operations (17 V, 1 mA)
• Tool-free snap-on front mounting - no adapters or additional wiring required

Applications:

• Safety monitoring in motor starter circuits using the mirror contact function
• Auxiliary interlocking and status signaling in 3RT2 contactor assemblies
• Control circuit feedback loops in machine automation panels
• Safety relay input circuits requiring positively driven NC contacts

Compliant with IEC 60947-4-1 and IEC 60947-5-1. Part of the Siemens SIRIUS 3RH29 range.

Also known as: Siemens 3RH2911-1FA04, SIRIUS 3RH29 4NC front auxiliary switch, Siemens front-mount auxiliary contact block.