Patent ID: 7311558

Claim:
A dimmable lighting unit for a lamp load capable of being operated from a selected one of a standard power supply or a dimmed power supply comprising: a plug electrically connectable to said lamp load; said plug adapted for insertion into a receptacle complying with an industry standard configuration for general-use plugs and receptacles, said plug further adapted to define a plug formation of a mating formation pair corresponding to a receptacle formation of said mating formation pair, said receptacle formation dimensioned to contact a general-use plug complying with said industry standard configuration and not defining said plug formation to prevent a blade of said general-use plug from contacting an electrical contact of said receptacle thereby preventing said general-use plug from establishing an electrical connection with said receptacle, said receptacle formation permitting insertion of the plug defining said plug formation by an amount sufficient to establish said electrical connection, wherein a full insertion of said plug defining said plug formation into said receptacle results in an overlapping contact between said contact and a first blade of said plug defining said plug formation, said overlapping contact having a length, and wherein the receptacle formation of said mating formation pair is a projection on the receptacle, the projection extending from said receptacle to a height that is greater than the length of said overlapping contact, and wherein the plug formation of said mating formation pair is a recess adapted for receipt of said projection such that said general-use plug is prevented from being inserted in said receptacle by an amount sufficient to establish said electrical connection.