B 400 relay – Safety critical, 4 contacts


The B 400 safety critical and heavy duty relay has 4 double make / double break C/O contacts (form Z). Weld no transfer safety contacts are standard. The plug-in design offers secure locking feature for maximum ease of maintenance (no wires need to be disconnected or other hardware removed for relay inspection or replacement).
The resistance to impact and vibration is conforming the standards for Railway Transported Equipment. Positive mechanical keying of relay to socket is built into relay and socket during manufacture and terminal identifications are clearly marked on identification plate that is permanently attached to the relay.


The B 400 relay is designed for ultra reliable heavy duty and safety critical applications such as door control, emergency brake failure, interlocking between traction and breaking around the world in countless railcars.


  • Instantaneous & safety critical relay
  • Plug-in design with secure locking feature for maximum ease of maintenance
  • 4 double make / double break C/O contacts (form Z), 12 A
  • Weld no transfer contacts standard
  • Contact life (mechanical) of 100 million cycles
  • -40 °C…+80 °C operating temperature


  • Proven reliable in heavy duty application
  • Long life cycle
  • Easy to maintain and replace
  • Used in safety critical operation
  • Low life cycle cost
  • No maintenance

Railway compliancy

  • NF F 62-002 Rolling stock- Instantaneous relays contacts and sockets
  • NF F16-101/102 Fire behaviour – Railway rolling stock




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