I currently have a bedroom in which a 15amp single pole switch is wired to the light in the room. Power is coming from the light. The two brass terminals on the switch have the white (which has black electrical tape) at the bottom of the brass screw. The hot is at the top of the brass terminal. Of course, the bare copper ground is on the green screw. The wiring is 12/2.
I have added a closet light switch tapping power from the light switch in the room using 12/2 wiring (I know it's overkill). I wired it with black from the light switch to black to the closet switch with a pigtail going to the bottom of the brass screw. However I capped the neutral wires (white) on the back of the added closet switch and another 12/2 cable is going from the top brass screw going to the closet light. As well as the white going to white of the closet. Bare to ground. The closet light bulb is only 40watts.
Now whenever I power on the closet switch light it powers on but the bedroom lights flicker and then turn off and the closet light dims in and out. Any reason why? The bedroom lights are 4 recessed lights that only use 65 watts. If I turn on the bedroom lights first and then the closet light, the closet light does not turn on until I switch off the bedroom switch light. Any ideas on how I can fix this? Thanks.
Best Answer
Your light and switch arrangement needs hot and neutral to function. You tapped it off the light switch in the bedroom, which only has hot and switched-hot (marked as white with black electrical tape). That is not a good place to get power. Here's what's happening:
With the bedroom switch on, the two pins on the switch are shorted out, so both power wires to the closet have the same voltage. It can't function.
With the bedroom switch off, current flows from hot, through your closet switch, through your closet lamp, and then through the bedroom lamps and to neutral. The lights are in series. That would light - dimly - with incandescents, but smart bulbs won't like it at all.
You cannot tap power at the switch if there's no neutral there. You should tap it at the bedroom light, where neutral is available.