Siemens 3RH2921-2DA11 SIRIUS Auxiliary Switch 1NO+1NC Spring Terminal

The Siemens 3RH2921-2DA11 is a SIRIUS laterally mountable auxiliary switch with 1 NO + 1 NC contacts, designed for snap-on fitting to the left or right side of 3RT2 contactors and 3RH2 contactor relays. Spring-loaded terminals allow tool-free conductor connection across the full 0.5-2.5 mm² range. Rated at 690 V insulation voltage with 6 kV surge voltage resistance, it suits demanding AC and DC industrial control circuits.

Technical specifications:

• MLFB: 3RH2921-2DA11
• Manufacturer: Siemens
• Product line: SIRIUS
• Contact arrangement: 1 NO + 1 NC (instantaneous)
• Terminal positions - left: 51/52, 63/64 / right: 31/32, 43/44
• 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
• Operational current AC-15 at 230 V: 6 A / at 400 V: 3 A
• IP rating (front): IP20
• Mechanical service life: 10,000,000 operating cycles
• Electrical endurance (AC-15 at 230 V): 200,000 operating cycles
• Ambient temperature (operation): -25 ... +60 °C
• Ambient temperature (storage): -55 ... +80 °C
• Mounting: snap-on
• Terminals: spring-loaded, 0.5-2.5 mm² / AWG 20-14
• Dimensions (W x H x D): 10 x 64.8 x 66 mm
• Weight: 47 g
• Compatible with: 3RT2.2, 3RT2.3, 3RT2.4, 3RH2

Features and benefits:

• Mounts laterally on left or right side of compatible contactors for flexible panel layout
• Spring-loaded terminals accept 0.5-2.5 mm² conductors without tools, including double termination
• Mirror contact function per IEC 60947-4-1 when paired with 3RT2 contactors
• Contact reliability of 1 faulty switching per 100 million operations at 17 V / 1 mA
• Certified for maritime and railway applications

Applications:

• Auxiliary signaling and interlocking in motor control centers using 3RT2 contactors
• Safety feedback and status monitoring in 3RH2 contactor relay panels
• Low-voltage AC control circuits up to 690 V in industrial switchgear
• DC control circuits from 24 V to 220 V in machine building and automation

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

Also known as: Siemens 3RH2921-2DA11, SIRIUS 3RH29 lateral auxiliary contact block, Siemens auxiliary switch 1NO 1NC spring terminal.