A motor control center subunit comprising: a subunit housing (18, 52) configured to fit within a motor control center and having a front panel; a drive mechanism attached to the subunit housing (18, 52) and configured to control a plurality of line connectors (46, 48, 50) to move between a retracted position and an extended position when the subunit housing (18, 52) is seated in the motor control center and the front panel of the subunit housing (18, 52) is in a closed position, wherein the plurality of line connectors (46, 48, 50) is configured to be connected with power supply busses (88, 90, 92) when in the extended position and wherein the plurality of line connectors (46, 48, 50) is enclosed within a clear housing; a window (436, 438) disposed within the front panel of the subunit housing (18, 52) and positioned to provide a view of the position of the plurality of line connectors (46, 48, 50); and a light sensor system disposed within the subunit housing (18, 52) and positioned to monitor a connection status of the plurality of line connectors (46, 48, 50) with the power supply busses (88, 90, 92); wherein the light sensor system comprises: a light emitting diode positioned on a first exterior surface of the clear housing so as to be on a first side of the plurality of line connectors (46, 48, 50); and a light detector positioned on a second exterior surface of the clear housing opposing the first exterior surface so as to be on a second side of the plurality of line connectors (46, 48, 50) opposite from the LED; wherein the light sensor system is configured to monitor a gap within the clear housing in which the plurality of line connectors (46, 48, 50) are configured to connect with the supply busses (88, 90, 92) based on light received by the light detector and emitted from light emitting diode, so as to monitor the connection status of the plurality of line connectors (46, 48, 50) with the power supply busses (88, 90, 92). a subunit housing (18, 52) configured to fit within a motor control center and having a front panel; a drive mechanism attached to the subunit housing (18, 52) and configured to control a plurality of line connectors (46, 48, 50) to move between a retracted position and an extended position when the subunit housing (18, 52) is seated in the motor control center and the front panel of the subunit housing (18, 52) is in a closed position, wherein the plurality of line connectors (46, 48, 50) is configured to be connected with power supply busses (88, 90, 92) when in the extended position and wherein the plurality of line connectors (46, 48, 50) is enclosed within a clear housing; a window (436, 438) disposed within the front panel of the subunit housing (18, 52) and positioned to provide a view of the position of the plurality of line connectors (46, 48, 50); and a light sensor system disposed within the subunit housing (18, 52) and positioned to monitor a connection status of the plurality of line connectors (46, 48, 50) with the power supply busses (88, 90, 92); wherein the light sensor system comprises: a light emitting diode positioned on a first exterior surface of the clear housing so as to be on a first side of the plurality of line connectors (46, 48, 50); and a light detector positioned on a second exterior surface of the clear housing opposing the first exterior surface so as to be on a second side of the plurality of line connectors (46, 48, 50) opposite from the LED; wherein the light sensor system is configured to monitor a gap within the clear housing in which the plurality of line connectors (46, 48, 50) are configured to connect with the supply busses (88, 90, 92) based on light received by the light detector and emitted from light emitting diode, so as to monitor the connection status of the plurality of line connectors (46, 48, 50) with the power supply busses (88, 90, 92). a light emitting diode positioned on a first exterior surface of the clear housing so as to be on a first side of the plurality of line connectors (46, 48, 50); and a light detector positioned on a second exterior surface of the clear housing opposing the first exterior surface so as to be on a second side of the plurality of line connectors (46, 48, 50) opposite from the LED; wherein the light sensor system is configured to monitor a gap within the clear housing in which the plurality of line connectors (46, 48, 50) are configured to connect with the supply busses (88, 90, 92) based on light received by the light detector and emitted from light emitting diode, so as to monitor the connection status of the plurality of line connectors (46, 48, 50) with the power supply busses (88, 90, 92).