Abstract: Means for connecting an electrical load system to a voltage source of a predetermined first voltage level for the operation of said system at optionally one of said first voltage level and a lower second voltage level, said means comprising an electrical plug element comprising a housing member, electrical conductor prongs extending from said housing member, and electrical conductor means electrically connected at one end thereof to said load system, said conductor means comprising separate first and second conductor paths electrically connected to respectively first and second said conductor prongs, said first conductor path comprising parallel first and second circuit paths electrically connected to said conductor prong associated with said conductor path, one of said circuit paths comprising an electrical rectifier element and another of said circuit paths comprising switching means that is open when said plug element is at a first orientation at said voltage source and closed when said plug element at a s