Abstract: An electrical device is supported on rails for racking movement between disengaged and engaged positions through an intermediate test position. The device mounts a single lead screw centrally located between the rearwardly extending device line and load terminal disconnects for threaded engagement with a caged nut fixedly mounted at a central location between the switchboard line and load terminal disconnects. A chain and sprocket drive train mounted by the device communicates rotational drive to the lead screw from a manual drive input applied at the front of the device to motivate racking movement between the disengaged and engaged positions. Interlocks are included to insure the device is off while the device and switchboard disconnects are being mated and unmated incident with this racking movement.