US Patent 9882313 Electrical plug adapter having socket key safety system

An electric vehicle (“EV”) charger plug adapter apparatus includes an adapter housing, a socket extending into a first side of the adapter housing, the socket configuration defined by a first technical standard for use with at least one of a first current or voltage rating, a plug extending from a second side of the adapter housing, the plug configuration defined by a second technical standard for use with at least one of a second current or voltage rating, and a key extending from the first side of the adapter housing, wherein the key prevents seating of a second plug into the socket if the second plug does not have a complementary key socket to fit the key.