I have a three way switch with power source at the light. In the switch boxes are 3 conducters, black, white, red, no ground or neutral this is a old house. Why would I not have 110v on any conducter when grounding to metal box, boxes have no grounds. I get any where from 3v to 50v on any one conducter when not grounding to anything. Also the metal switch box seems to have 3v-4v when not grounding to anything?