Description   
2.7 Basic unit 
  3VA27 molded case circuit breakers & 3WL10 air circuit breakers 
32  Manual, 10/2018, L1V30499596002-01 
 
Design of the circuit breaker 
The circuit breaker contains the contacts (3 or 4 poles), the switching mechanism, and the 
internal accessories, comprising an operator and contact system and the internal 
accessories. Each of the poles is contained in a separate plastic enclosure and consists of 
the interrupting contact system and a current transformer. 
Main components of the 3VA27 & 3WL10 circuit breakers 
 
Area with front / rear connections 
Auxiliary conductor terminal system 
Electronic trip unit (ETU) 
Switch position indicator contacts OPEN / CLOSED 
"Mechanical ON" pushbutton 
"Mechanical OFF" pushbutton 
Status indicator of spring energy store CHARGED / DISCHARGED 
Manual lever for charging the spring energy store 
Toggle operating mechanism 
PUSH TO TRIP: initiates a mechanical trip