Adding a dimmer to Potlights

Old 12-02-12, 11:05 PM
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Adding a dimmer to Potlights

Hi all,

First time post, so just want to say this forum is great, so thanks in advance.

I recently moved into a new house in Ontario, Canada. In it, I got pot lights installed, and they go to a box with 2 switches in it (the second switch is for a currently non-existent ceiling fan that they wired for me).

I purchased 2 dimmers, and installed one on another set of potlights, and it was fine, as it was the only switch in the box. Unfortunately with this one, it has 3 wires, one of which goes to the switch beside it.

The dimmer I purchased is a Leviton 6631-L. A PDF with instructions and diagrams can be found here:

With this one I have tried pretty much every combination of the wires, using only 2, or using all 3 (plus ground of course) and none have worked properly. I keep running up and downstairs to the fuse box, making small changes, but I feel like I must be missing something. Sometimes the switch switches off the entire circuit (all the plugs on the same line from the fuse box), and sometimes it does nothing.

Here is an image of the wiring in the box. The second switch is just one wire in the top, and one in the bottom, you can see them coming off the side of the picture.

Thanks again.
Old 12-03-12, 12:59 AM
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Nice picture but it doesn't tell us everything.

How many cables are in that box ?
A cable is a white, a black and a ground.

I'm going to make some assumptions to keep this moving.

You have four cables in the box:
One cable is power in
One cable is power out
One cable (pretty blue) ceiling lights
One cable (pretty blue) future fan

All 4 white wires go to one common wire nut. That connects all neutrals together. That's fine.

I can't see the ground wires so I'll leave that up to you.

There is a black wire that comes in the bottom of the box. It goes to both switches. That is the feed in to the box. It feeds both switches and then also needs to feed the power out cable.

I've assumed that the two blue wires (romex ?) coming in the top of the box are the wires they just ran to your lights and future fan.
Each of those black wires go to the open terminals of a switch.

The extra black wire that we haven't talked about is the power out of the box and it feeds your outlets. This wire needs to connect to the other wire that comes in the bottom of the box.....the black wire that connects to both switches.

Technically both of the two black wires that come in from the bottom of the box should be connected together with two tails coming out to the switches. Right now you are using the screw terminals to bring power to the switches and the stab on the switch to power your outlets.

Hope this makes sense. If I mis-counted cables then this will change slightly.
Old 12-03-12, 04:18 AM
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I believe PJ has it covered. However, it appears they used a good quality set of switches, since they appear to be able to take two wires under one screw, without crooking them. Stab backs should be removed to screws in any event. Pigtailing is the best way to handle multiple wires going to one screw location.
Old 02-05-13, 07:44 AM
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Just wanted to update and say thanks guys. I eventually determined (thanks to your comment and additional research) that I needed to combine the wire going into the bottom socket in addition to the one that is looking, and then add the wire from the dimmer to those two combined. After doing that, it worked fine.
Old 02-05-13, 08:22 AM
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Glad we could help. Thanks for letting us know the outcome.

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