Siemens 3RH2921-2DA02 SIRIUS Auxiliary Switch 2NC Lateral 690V

The Siemens 3RH2921-2DA02 is a SIRIUS lateral auxiliary switch with 2 NC instantaneous contacts, designed to snap-on beside 3RT2 contactors and 3RH2 contactor relays. It delivers feedback and interlocking signals via left-side contacts at 51/52 and 61/62 and right-side contacts at 31/32 and 41/42. Rated for 690 V insulation voltage and up to 10 A at AC-12, it uses spring-loaded terminals for tool-free wiring.

Technical specifications:

• MLFB: 3RH2921-2DA02
• Manufacturer: Siemens
• Product line: SIRIUS
• Product type designation: 3RH29
• Contact arrangement: 2 NC instantaneous
• Left contacts: 51/52, 61/62; right contacts: 31/32, 41/42
• Insulation voltage: 690 V AC
• Surge voltage resistance: 6 kV
• Operational current AC-15 at 690 V: 1 A
• Operational current AC-12 maximum: 10 A
• IP rating: IP20 (front)
• Mechanical service life: 10,000,000 operating cycles
• Electrical endurance: 200,000 cycles at AC-15, 230 V
• Operating temperature: -25 to +60 °C
• Storage temperature: -55 to +80 °C
• Mounting: snap-on
• Terminal type: spring-loaded
• Conductor cross-section: 0.5 to 2.5 mm²
• Dimensions (WxHxD): 10 x 64.8 x 66 mm
• Weight: 46 g
• Suitable for: 3RT2.2, 3RT2.3, 3RT2.4, 3RH2

Features and benefits:

• Lateral snap-on mounting integrates directly beside 3RT2 contactors and 3RH2 relays without additional hardware
• Spring-loaded terminals accept 0.5 to 2.5 mm² conductors for fast, tool-free wiring
• Mirror contact function per IEC 60947-4-1 when paired with 3RT2 contactors
• 10 million mechanical operating cycles for extended service life
• Dual-side contact paths at left and right allow flexible panel layouts
• Compact 10 mm wide profile minimises space in control panel assemblies

Applications:

• Motor starter feedback and status indication circuits
• Safety interlocking in 3RT2 contactor assemblies
• Auxiliary signaling with 3RH2 contactor relays
• Machine safety circuits requiring mirror contact verification
• Low-voltage switchgear and control panel auxiliary circuits

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

Also known as: Siemens 3RH2921-2DA02, SIRIUS 3RH29 lateral auxiliary switch, Siemens 2NC auxiliary contact block.