The Siemens 3VA9278-0CB10 is a SENTRON Max-Flex switch module — a Bowden wire actuator designed as a remote operating accessory for 3VA molded-case circuit breakers. It's the piece that lets you trip or reset the breaker from a distance, which matters when the breaker is buried inside a panel or behind a locked door.
Compatibility and Mounting
This accessory is listed for the 3VA5 250 and 3VA6 150/250 frame sizes. The Bowden cable gives you mechanical remote operation — no electrical control wiring needed, just a cable run. Mounting is straightforward: the module clips onto the breaker's accessory slot, and the cable routes to a remote operator handle or pushbutton station.