A circuit breaker assembly includes a housing, an electrical bus structure within the housing, a number of first plug-in members coupled to the bus structure, and a number of insulative retainers coupled to the bus structure. A corresponding one of the number of insulative retainers is operatively associated with a corresponding number of the number of first plug-in members. Each of a number of circuit breakers includes a manual operator and a number of second plug-in members disposed opposite the manual operator. The number of second plug-in members electrically engage a number of the number of first plug-in members. The corresponding one of the number of insulative retainers is disposed about the corresponding number of the number of first plug-in members, in order to insulate the corresponding number of the number of first plug-in members, and to retain the number of second plug-in members.