Main Components of a Circuit Breaker

Major parts and subassemblies of molded and insulated case breakers may include:
Contact saddle with gang-operated contact holders and contacts
Switching mechanism
Phase barriers
Molded or insulated case, bottom or base
Case cover, sometimes including manual operating lever
Sometimes removable and sometimes stationary polebases with stationary contacts mounted
Line and load conductive pads, connectors, braids
Trip unit(s), programmers
Current sensors or current transformers
Flux shifter
Trip bar
Accessories and auxiliaries, shunt trip, undervoltage release, aux contacts, aux switch
Charging motor or motor operator
Fuses on control power or for current limiting
Terminals or lugs