In new Double Gang, one light goes on only when other is on.

[mdenglund]

Hi, All!

I am adding a recessed light to our basement closet by tapping into the power at an existing switch in the room that powers the bedroom light. I expanded to a double gang, installed all, but the closet light only goes on when the bedroom light is on...?? The previous setup on the switch for the room light (which included two 14/2 cables, four wires w/o grounds) was blacks onto screws on switch and whites capped together.

So, my new config (with the added 14/2 from the new closet light) is all whites capped (now 3 of them), I pigtailed one black (which I think is power) – one pigtail connects to old switch and one to the new. Then, the remaining black from the light in bedroom and the other from the closet light connect to the second screw on each corresponding switch. In other words, pigtailed black ‘power’ in top screw on both switches, and second black from each fixture in bottom screw.

Does anyone have thoughts on why one switch must be on for the other to work?

Thanks in advance for any help!
Marty

 

[RedHerring2]

You've tapped off the switch wire, not the live wire.
But it's difficult to understand your american terminolgy.

 

[OwainDIYer]

Hi, All!

I am adding a recessed light to our basement closet by tapping into the power at an existing switch in the room that powers the bedroom light. I expanded to a double gang, installed all, but the closet light only goes on when the bedroom light is on...?? The previous setup on the switch for the room light (which included two 14/2 cables, four wires w/o grounds) was blacks onto screws on switch and whites capped together.

So, my new config (with the added 14/2 from the new closet light) is all whites capped (now 3 of them), I pigtailed one black (which I think is power) – one pigtail connects to old switch and one to the new. Then, the remaining black from the light in bedroom and the other from the closet light connect to the second screw on each corresponding switch. In other words, pigtailed black ‘power’ in top screw on both switches, and second black from each fixture in bottom screw.

Does anyone have thoughts on why one switch must be on for the other to work?

Thanks in advance for any help!
Marty

From where are you getting your neutral?

 

[Paul_C]

Hi Marty,

As noted above, you've tapped into the wrong black wire, so you need to move the connection you made for your new switch for the closet light onto the black wire which is on the other side of original switch, as that will be the permanently hot feed.

In other words, following your top & bottom terminal descriptions, the black wire going to the top terminal of your new switch to provide power for the new closet light should be pigtailed with the black wire which currently goes to the bottom terminal of the original switch.

From where are you getting your neutral?

He's tapped it from the whites which were already running through the switch box. (Unless there was something very screwy going on with the existing wiring.)

 

[mdenglund]

Thank you very much, Paul! Great description and this worked perfectly! I wish I could admit I would have figured this out on my own, but that is not likely... However, now that I see it, it makes a lot of sense.

Thank you again and everyone else for the thoughts!