An electrical busway plug-in unit includes a pair of restraint mechanisms extending through the housing of the plug-in unit for mechanically attaching the plug-in unit to the busway. Each restraint mechanism includes a rotatable shaft extending through the front wall of the housing, and a knob attached to the front end of the shaft, on the exterior side of the front wall of the housing, for manually rotating the shaft. A mechanical connector projects rearwardly from the rear wall of the housing and extends forwardly into the interior of the housing where the connector is coupled to the shaft so that rotational movement of the shaft in opposite directions moves the connector into and out of latching engagement with the busway.