An interlockable lock-out handle system for an electrical switching device includes a lock-out rim and a lock-out handle. The lock-out rim is configured to be disposed over an operating shaft of the switching device and fastened to at least one of switch housing and a front plate. The lock-out handle is configured to be fastened by a clamping device in rotational engagement on the operating shaft. The lock-out handle includes a rotary handle having a grippable lateral surface and a lock-out collar. The lock-out collar is vertically displaceable relative to the rotary handle in a direction of a longitudinal axis of the operating shaft into a CLOSED position and an OPEN position. The lock-out collar is engaged with the lock-out rim so as to prevent twisting movement of the lock-out collar relative to the lock-out rim when the lock-out collar is in the CLOSED position.