I have an older home and was updating some of the light switches. One room looks as though someone attempted to wire a 3-way switch, but it was obviously done incorrectly. The main problem I have run into is that it doesn't appear to be a ground wire. The switch that is currently there has 3 screws 2 silver and a copper. The silver screws have 1 white and 1 black wire going to them and the copper screw has a black wire going into it. Is it possible that the black wire going into the copper screw is the ground or is there no ground wire in the switches. Both switches are wired exactly the same, but like I say there is no green wire or screw. How can this be fixed safely?