I am having some problems figuring out the shop lights. There is one central junction box in the middle of the garage ceiling. It has one cable for power in and one for the wall switch. I was using a lighted switch.
From the hot lead in to either of the switch conductors I read 20 volts. About 10 volts to my aluminum ladder on a dry concrete floor.
I first tried to use a wago connector to tie the incoming hot lead to the switch. I did it with the power on so I could measure voltages and make sure I had it correct. I saw arcing and it got hot enough to melt. So there is more then just stray voltage. Once it was connected it cooled off and did not melt anymore. I had to let it cool a little while while I ran and got pliers since it had burned my fingers connecting.
I think the switch ground is also good, 120 volts. This is modern plastic insulated romex , 1969. There is no conductivity between any of the three wires to the switch box.
Maybe if I did this with the power off I would have never known?
Bill D