The available interlocking devices can be used to implement a mutual interlock between at least two 3VA molded case circuit breakers.

The interlocking device only ever releases one 3VA molded case circuit breaker at a time, thereby ensuring that only the released circuit breaker can be operated. All other 3VA molded case circuit breakers remain in the safe OFF (O) position and are blocked by the interlock.

Principle of two mutually interlocked 3VA molded case circuit breakers:


Molded case circuit breaker blocked/locked in the safe switching state OFF (O)

Molded case circuit breaker released for operation

The following interlocking systems are available for 3VA molded case circuit breakers:

Front interlock

All front interlocks are installed on the front panel of the 3VA molded case circuit breaker. Front interlocks make it impossible to install some other external accessories such as motor operator, rotary operators, etc. They also partially restrict access to internal accessories compartments.

Rear interlock

The rear interlock does not affect the front panel of the 3VA molded case circuit breaker. All components of the interlocking system are concealed behind the molded case circuit breaker or the mounting plate.