The Siemens 3VA9978-0AA11 is an auxiliary switch designed for 3VA series molded-case circuit breakers. It provides additional changeover contacts that enable signalling and control functions alongside standard breaker protection.

Built for demanding environments, this switch operates reliably at voltages up to 600 V AC or 250 V DC, with a thermal current rating of 10 A. It maintains steady performance under vibration, temperature variation, and electrical load, ensuring dependable auxiliary switching in industrial applications.

The 3VA9978-0AA11 installs easily into compatible breaker frames without altering their protection or footprint. Its compact design keeps control panels tidy while adding flexibility for system monitoring, interlocking, and automation control.

This accessory is ideal for use in switchboards, control panels, and power distribution systems where auxiliary status indication or remote signalling is needed. It offers long service life, high reliability, and seamless integration with the 3VA product family.