Apparatus for substantially eliminating exposure to live parts on a busway plug-in unit enclosure includes a power take-off with male-terminal stabs which are capped with nonconductive material. A nonconductive structure covers the bus assembly and allows only the stabs to pass into the interior of a plug-in unit enclosure. A shutter assembly in each plug-in unit enclosure has a nonconductive shutter plate that moves only longitudinally along the stabs when a plug-in unit device is inserted into the enclosure. Inserting the plug in unit device into the enclosure causes a shutter plate latch to open and depress the shutter. When the plug in unit device is removed from the plug in unit enclosure, the shutter plate is biased upward and latched in a position over the stabs. No live touch points are available in the enclosure.