I have an older house with a small new back entry addition. This light switch for the ceiling lights is in the older part of the house. There are two lights and they both have live wires even when they are turned off. One light has the wiring exposed and has only one cable to it. The wiring for the other light is concealed in the ceiling. I can’t figure out how turning the light on would cut off the power to a wire running to (or from) the switch.
I have a complete mystery. When I turn a light on the light goes on, but both wires to the switch show no power. When the light is turned off, one of the wires to the switch becomes hot. I have tested this with both non-contact and contact connectors.