Give me the exact model number of your non-contact detector. I’ll look at the manual. [quote=“jt114881, post:14, topic:50935”]
Would the gang box for the recessed lighting be under the light itself? I can’t think of any other place it could be unless it is hidden behind a wall.
It is up in the light itself. If you do a search on recessed can you’ll see what I mean or take a look at one at your local HomeDepot or Lowes.
If it were me, I would take down the hanging lights to see how they wired up my lights there first because those are standard boxes you can easily get to and photograph. Then you could take off wire nuts to isolate and confirm everything from where is the hot coming from, etc. and what did they pass down to the switch. By doing this we could see how you are getting this weird voltage. on both lines from.
Not sure what you were trying to find out by joining the whites together? The romex (black, white, ground) is your switch leg to one light circuit. You inadvertently connected to separate lighting circuits together. Since they both are fed by the same circuit and that both are switch legs only it wasn’t a safety issue but if you were trying to manually trigger your LED lights you need to join the black and white of the same romex.
It shouldn’t hurt a thing but I am assuming that your electrician used a typical installation. Disconnect the wires off the switch. When you get your volt-ohm-meter you can measure the AC volts from the black to the neutral(from adjoining box) and you should see the 110V. Measure again from the same romex but the white wire back to the neutral and you should see 0V.