Siemens Sentron 3VA Manual page 306

Accessories
4.7 Locking and interlocking
Principle of two interlocked 3VA UL molded case circuit breakers:
①
②
The 3VA UL molded case circuit breakers provide the following interlocking options:
● Front interlock
● Rear interlock
Front interlock
All front interlocks are installed on the front panel of the 3VA UL 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 accessory
compartments.
Rear interlock
The rear interlock does not affect the front panel of the 3VA UL molded case circuit breaker.
All components of the interlocking system are concealed behind the molded case circuit
breaker or the mounting plate.
304
Molded case circuit breaker blocked/locked in the safe switching state OFF (O)
Molded case circuit breaker released for operation
3VA molded case circuit breakers with UL and IEC certification
Manual, 01/2019, L1V30435333-01