Bedroom, during a remodel, we put a double gang box in so I could have a switch for a closet light. Wiring for that is in. (this was 3 years ago, some family things put off completion, and my installer isn't available). Today I pulled out the working switch for the room light. It had 2 hot wires (looks like in one sheath). No neutral wires seen.
I took off of the top wire to the switch, placed a new black wire to the top connection on the switch and one to the hot. (using wire screw) Light works. I then took another new black wire to the hot/new wire (using a wire screw) put that to the top of the new switch. Took the black from the new wiring to the closet to the bottom of the new switch.
This leaves a neutral from the new wiring to the closet light with no where to go. And the closet light does not work in this configuration.
I have replaced several switches, outlets over the years, first time I've come upon this issue.