Hi! I have an issue... and I've been looking and looking but haven't found anything like this reported anywhere. Here's the issue:

Just got in my brand new condo and the wife wants dimmer switches in the bedroom and dining room.

Went to Home Depot, got 2 dimmers (Lutron CFL dimmer) and 2 CFL dimmable (20w = 75w) lightbulbs.

Plugged in the one in the dining room. So far so good.

Then got in the bedroom. The light flickers on/off when I try to dim, and it dims, but flickers (ie. it stays on at 100%, then flickers from 80% down, but the intensity of the light, when it's on, is dimmed!)

For that specific situation, under "troubleshooting" in the manual it says to find the +/- wattage switch on the dimmer and play with that. Doesn't fix the problem.

But here's where it gets amusing: when the dimmer in the dining room is on, the one in the bedroom wont even turn on!

They're all on the same breaker in my switchbox. It's a 15 amp breaker. The lightswitches are 3-way.

I tried to troubleshoot. Here's what I did:
- Tried 9 different wirings. No change.
- Switched the 2 dimmers (bedroom->dining room and vice-versa). No change.
- Turned down the +/- wattage switch on the working dimmer and turned it up on the non-working dimmer. No change.
- Played with the lights that are on the same breaker. It doesn't affect the dining room dimmer, but it affects the bedroom one.

I'm all out of solutions. Please help.

 

Is the dimmer compatible with a three way set up? Are you sure about the dimmability of the bulbs? Where is the other switch for the bedroom light? Do the dimmers have a neutral (white) wire on them?

 

Is the dimmer compatible with a three way set up? - Yes, it's in the manual

Are you sure about the dimmability of the bulbs? - Yes, it's written on the box with big bold red letters
Where is the other switch for the bedroom light? - There is none

Do the dimmers have a neutral (white) wire on them? - No, they have a white/red wire, which is probably what you are referring to

 

Try a regular light bulb and see if it dims.

Does your dimmer have a minimum wattage listed on it ? Some are 40 watts.
That means it needs 40 watts of CFL load to dim correctly.

 

I did, with a 100w regular lightbulb. Same thing.

(Thanks for your help, guys.)

 

Something isn't right. If they are 3 way, there has to be two of them.

 

I know but it's not the case. In the dining room it's a 3-way and I thought nothing of it because it's in a double box with the light for the kitchen. But in the bedroom, it's a 3-way setup with only one switch! The light turns on even without the neutral cable being connected, for some reason.

 

Could you post pictures of the wiring at the light and switch with them pulled out so we can geta good view. http://www.doityourself.com/forum/li...-pictures.html

 

Here it is.
As you can see, it's black or white.
I had a hard time figuring out that the cable coming out of the top left is the positive. But it also works reversed - I tried all possible combinations.

Basically there's only one combination that doesn't work: when I connect the neutral in the box to the positive on the dimmer. All the other ones work.

 

I''ll bet since there are no positives in an AC circuit. Do you mean the cable was hot when you measured with a multimeter or test light between the black and white of the cable?

What you have is not a three way set up. You have a line (the hot cable) feeding to loads (the other two cables), maybe lights, maybe receptacles. The line black is
is connected to the switched load on one cables through a switch and directly to the unswitched load on the other cable. One load black is connected to the other screw of one switch and the second load black to the second screw on the other switch.

 

Hm. I was under the impression that since there's a red, a red/white and a black wire coming out of the dimmer switch that I needed to connect a "positive" to the red one. Obviously I was wrong. Thank you for that.

Is there something I can do to get both dimmers to work?

 

The dimmer switch is usable for both a 3-way setup and a single location switch setup. One of the wires is capped off and not used for a single location switch setup such as you have. It is probably the red/white wire but you need to read the instructions to be sure. If both load cables are to lights you will need a dimmer or a regular switch for each one. Most likely the switch black goes to line black and that leaves the red to load black but check the instructions.

 

Thank you very much for your help Ray.
I'm at it again.
I read the instructions for a single pole setup. As per said instructions I capped off the red-white wire that comes out of the dimmer. Then, I tried all possible combinations. All led to the same symptoms as before (meaning that or the light flickers on-off when dimming + doesn't work at all when dining room switch is on OR the light doesn't work at all, depending on the configuration.)
What throws me off is that there are 3 black wires coming out of the wall. Does that mean that 2 of them would need to be connected together? Or do I just need to leave one of the 3 alone? I left one of the 3 alone and tried all possible combinations with no results.

 

No. You do not have three black wires. You have three two conductor cables. Each cable contains a black and a white wire. There is NO + there is one hot cable and two cables that are not hot that carry power to other devices. If only one switch is used the black of the cable from the unswitched load goes to the black of the hot cable along with the dimmer black.

 

Well, that's what I thought at first, but it didn't solve my problem, so I'm trying to go beyond that.
How can I get it to work?
Manual says, single pole, you isolate the red-white, and connect the black to a cable and the red to another. Did that. Doesn't work. Now what?
Thanks for your help once again!

 

I have given you somewhat misleading information. I have revised my previous posts. Perhaps reread them. Sorry for the confusion.

It is important that you are sure of which cable is hot. That can not be done with a non contact tester. It is done by measuring between the bundle of whites and each disconnected black using a multimeter or test light.

It is important you determine which cable goes to the light. Once you have verified which cable is hot chose one of the two remaining cable blacks and connect directly to the hot cable black. If the light you want to dim lights up that is your switched cable. If not disconnect and repeat the test with the black of the other cable. The cable black that is not connected to the light is your unswitched hot mentioned below. During tests all whites should remain connected together.

Your connections are:

• All whites together.
• Hot black, unswitched black, dimmer black together.
• Dimmer red and switched black(black to your light) together.

 

Yep. Top left is hot, top right goes to the light, bottom right doesn't do anything (unswitched).

What do I do now?

I've connected top left to red and top right to black
I've connected top left to black and to right to red
Both do the exact same thing: light lights up, then goes on and off when I try to dim.

(I'm really confused.)

 

Sounds like a bad dimmer. I suspect you fried it with your wire swapping.

 

Yes. The black wires entering at the top left and bottom right need to be spliced together and to the input (LINE) (black?) wire on your switch. The black wire entering at the top right needs to be spliced to the output (LOAD) (red?) wire on your switch. If your switch has a white wire, it needs to be added to the existing 3-wire splice of white wires.