Rotary switch interlock mechanisms and electrical switch assemblies with a rotary switch interlock mechanism are presented herein. An electrical distribution device with at least two electrical switches is disclosed. Each of the electrical switches has a switch actuator that is movable between engaged and disengaged positions. A rotary interlock member is rotatably mounted to the housing of the electrical distribution device adjacent the first and second electrical switches. The rotary interlock member is rotatable 180 degrees between a first orientation, whereat the rotary member allows the switch actuator of the second electrical switch into its engaged position while preventing the switch actuator of the first electrical switch from being moved into its engaged position, and a second orientation, whereat the rotary member allows the first switch actuator to be moved into its engaged position while preventing the second switch actuator from being moved into its engaged position.