Accessories 
  3.5 External accessories 
3VA27 molded case circuit breakers & 3WL10 air circuit breakers 
Manual, 10/2018, L1V30499596002-01 
117 
The circuit breaker can be locked via the front mounted rotary operator in three different 
ways. 
1.  On the handle: 
With up to three padlocks (5-7 mm diameter) 
2.  On the rotary operator: 
With up to three padlocks (5-7 mm diameter) 
3.  With cylinder lock on the rotary operator: 
The circuit breaker can also be prevented from closing with a key and an optionally 
installable cylinder lock. 
 
External accessories 
3.5.1
 
External digital I/O module IOM300 
The external digital I/O module IOM300 provides 11 input and 10 output contacts for control 
and remote signaling of alarms and tripping of the circuit breaker. 
It is suitable both for the electronic trip units of the 6-series and of the 3-series because it is 
connected directly to the CB1 and CB2 terminals of the auxiliary conductor terminal system.