Siemens 3RH2911-1LA11 SIRIUS Auxiliary Switch 1NO+1NC Front Screw

The Siemens 3RH2911-1LA11 is a SIRIUS front-mount auxiliary switch with 1 NO and 1 NC instantaneous contacts at terminals 73/74 and 81/82, designed to snap onto the front of 3RT2 contactors and 3RH2 contactor relays. Screw terminals accept conductors from 0.5 to 2.5 mm² with cable entry from the top, rated for insulation voltages up to 690 V AC.

Technical specifications:

• MLFB: 3RH2911-1LA11
• Manufacturer: Siemens
• Product line: SIRIUS
• Product type: Auxiliary switch, front snap-on mount
• Compatible with: 3RT2.1, 3RT2.2, 3RT2.3, 3RT2.4, 3RH2
• Contact arrangement: 1 NO + 1 NC instantaneous (73/74, 81/82)
• 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 at 24 V / 230 V: 10 A
• Mechanical service life: 10,000,000 operating cycles
• Electrical endurance (AC-15, 230 V): 200,000 operating cycles
• IP rating (front): IP20
• Operating temperature: -25 ... +60 °C
• Mounting: Snap-on to front
• Terminals: Screw-type, cable entry from top
• Conductor cross-section: 0.5 ... 2.5 mm² (solid, stranded, or finely stranded with core end processing)
• Dimensions (H x W x D): 37.5 x 36 x 43.7 mm
• Weight: 56 g
• Short-circuit fuse protection: gG 10 A, 690 V, 1 kA
• Short-circuit MCB protection: C10, 0.4 kA (up to 230 V)

Features and benefits:

• Mirror contact per IEC 60947-4-1 when paired with 3RT2 contactors, enabling safe position feedback
• Positively driven operation per IEC 60947-5-1 for use in safety-related circuits
• 10,000,000-cycle mechanical service life reduces maintenance intervals
• Accepts two conductors per terminal (2x 0.5-1.5 mm² or 2x 0.75-2.5 mm²) for flexible wiring
• Snap-on front attachment requires no separate mounting hardware

Applications:

• Status signalling and interlocking in 3RT2 motor control circuits
• Auxiliary contact expansion for 3RH2 contactor relays in control panels
• Safety circuit monitoring using the mirror contact function
• Control circuit feedback in low-voltage switchgear assemblies

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

Also known as: Siemens 3RH2911-1LA11, SIRIUS 3RH29 front auxiliary contact block.