Accessories
4.4 Plug-in and draw-out technology
3VA molded case circuit breakers with IEC certificate
272
Manual, 03/2019, A5E03603177010-03
4.4
Plug-in and draw-out technology
4.4.1
Introduction
With most applications, 3VA molded case circuit breakers are installed in a fixed position in
switchboards or distribution boards. The breaker is normally secured by mounting screws
directly to the mounting plate or other suitable supporting stays of the panel. The cables or
busbars of the main circuits are connected directly to the 3VA molded case circuit breaker by
various terminals or connectors. A rigid, permanent connection is thus created between the
3VA molded case circuit breaker and the panel.
For certain applications, e.g. cyclic inspections or service, it must be possible to replace the
3VA molded case circuit breakers quickly. To meet this requirement, 3VA molded case
circuit breakers can be converted to plug-in and draw-out units.
The main differences between plug-in units and draw-out units are convenience of operation
and the potential for functional expansion.
Plug-in technology
Plug-in technology is the less expensive and more space-saving of the two solutions. The
3VA molded case circuit breaker is inserted in the appropriate plug-in socket and fitted with
plug-in contacts which make a keyed, friction-locked connection with the corresponding
mating contacts (tulip-type contacts) in the plug-in socket. In this case, the device is plugged
in and withdrawn manually.
