Abstract: An apparatus for mechanically limiting a plurality of switch type circuit breakers mounted in linear alignment so that a predetermined number of circuit breaker switches can be in a predetermined position at a time, generally ON, and whereby access to all remaining switches is prevented and the unintentional operation of all remaining switches is prevented. A rigid housing is provided for mounting a plurality of switch-type circuit breakers in linear alignment. An interlock plate is slidably mounted to the housing adjacent the breaker switches. An opening through the interlock plate allows access to the predetermined number of switches which are to be accessible. The solid portion of the cover prevents access to the remaining switches and locking bars on the bottom face of the interlock plate mechanically limit movement of the remaining switches. In order to move the interlock plate to access other breaker switches, all switches must be in the same position, generally OFF.