Siemens SIRIUS Auxiliary Switch Block 4 NO (3RH2911-2FA40)

The Siemens 3RH2911-2FA40 auxiliary switch block expands the contact configuration of SIRIUS 3RT2 contactors and 3RH2 contactor relays with four normally open (NO) contacts. Unlike single-purpose add-on blocks, this front-mounting unit uses screw terminals for secure wiring and provides clear terminal designations (.1/.2) for straightforward integration.

Highlights

• 4 normally open (NO) contacts for control and signaling tasks
• Front mounting on compatible SIRIUS contactors and contactor relays
• Screw terminals for reliable conductor connection
• Rated insulation voltage 690 V and impulse withstand 6 kV
• Operating current up to 6 A (AC-15, 230 V) and 10 A (DC-13, 24 V)
• Mechanical durability of 30 million switching cycles

In daily use

This auxiliary switch block is suited for industrial control panels where additional NO contacts are needed for status feedback, interlocking, or load switching. Its IP20 degree of protection is intended for installation inside enclosures. The operating temperature range from -25 °C to +60 °C covers typical machine room and factory floor conditions.

Full specifications

• Number of NO contacts: 4
• Number of NC contacts: 0
• Mounting type: Front mounting
• Connection type: Screw terminal
• Rated insulation voltage (Ui): 690 V
• Rated impulse withstand voltage (Uimp): 6 kV
• Operating current AC-15 at 230 V: 6 A
• Operating current DC-13 at 24 V: 10 A
• Degree of protection: IP20
• Ambient operating temperature: -25 to +60 °C
• Electrical durability: 10 million switching cycles
• Mechanical durability: 30 million switching cycles
• Compatibility: Siemens SIRIUS 3RT2 contactors, 3RH2 contactor relays
• Terminal designation: .1/.2

Final note

Use this block to add four NO contacts to your SIRIUS switching device without changing the base unit.