The present invention is directed to a system for modifying a circuit breaker for removable installation in a cell of switchgear system, wherein the unmodified circuit breaker is not adapted for mounting in the cell. The system includes an adapter frame to which the circuit breaker is mounted and gear assemblies mounted to opposing sides of the circuit breaker. The gear assemblies adapt a racking device of the circuit breaker so as to be operable to rack the circuit breaker within the cell of the switchgear system.