This cable went to a box that had a GFCI and a switch. It only has two wires, hot and neutral. It was a metal box and there was also a separate ground wire attached to the metal box (green) that I traced back to a receptacle that is on a different circuit. I want to reconnect this cable to a new GFCI, but will it work with no ground? Obviously not, but what do I hook the ground up to? This green ground was connected to the metal box, but my new box will be plastic. Can I hook up a ground wire to the GFCI outlet that is attached to another circuit? These outlets all previously worked.