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Old 02-09-2009, 08:15 PM   #1
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An odd question


First off I just bought my house and replaced the light bulbs in the master bedroom fan with CFL's. I noticed the dimmer switch in the master bathroom was getting really hot. It has 8 60watt bulbs in the light.

I replaced the dimmer and I noticed they had the green ground wire attached to the white neutral wire, one black was to hot and the other black was to the screw for the switch. Nothing was attached to the ground wire.

I replaced the switch with another dimmer and attached the green wire to the ground wires, one black to the black hot wire, and the other black to the neutral.

The switch still gets hot. Is that because it is feeding 8 60 watt bulbs? And now the CFL's in the ceiling fan flicker when they get hot with the bathroom lights off. When the bathroom lights are on they don't flicker.

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Old 02-09-2009, 08:21 PM   #2
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An odd question


You cant use cfls with dimmer unless they are rated for such use.

Replace with dimmable cfls.

The switch wiring is confusing, do you have a picture of it? Normally you don't have 2 blacks with one cable...unless there are more cables?

This doesn't make sense with the fan and bathroom, are they on the same circuit?

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Old 02-09-2009, 08:35 PM   #3
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An odd question


The CFL's are not on the dimmer. They are in the fan, but they flicker if the bathroom lights are off.
I think they are on the same circuit because of the issue.

Edit: I don't know much about AC electricity, but I could find any electrical problem in your car.
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Old 02-09-2009, 08:39 PM   #4
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An odd question


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Originally Posted by 2long4u View Post
The CFL's are not on the dimmer. They are in the fan, but they flicker if the bathroom lights are off.
I think they are on the same circuit because of the issue.
You may have a multi-wire branch circuit that is wired incorrectly. When you disconnected that neutral from ground you may have broken the neutral of the circuit, which was incorrectly flowing through a ground wire.

You will need to do some testing to confirm this theory though. I'm out on a limb since we don't have a whole lot of information from you at this point.
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Old 02-09-2009, 08:43 PM   #5
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An odd question


Well I didn't like the fact of the switch getting hot and thought it may be because of the load. I bought a bunch of cfl's today and will be getting rid of the dimmer. I will take some pics of the wiring. There were at least 3 white wires in the box. What other info do you need and what can I check?
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Old 02-09-2009, 08:45 PM   #6
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An odd question


Try to figure out what neutral is supposed to be going back to the panel. Make sure that neutral actually does go back to the panel.

Inside the switch box, you should have less than 1 ohm between the ground wire and the neutrals. If you don't get continuity there then you have a floating neutral system which could cause the symptoms you described if it's a MWBC.
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Old 02-10-2009, 12:43 AM   #7
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An odd question


I was wrong. I did connect everything correct. I still don't know why the CFL's were flickering, but I did end up taking out the transmitter.
I took out the dimmer and will be putting that on a some 12v lighting that I have.
I will be replacing the regular bulbs in the bathroom to some decorative CFL's. Hopefully that will get rid of some of the hear they produce.
Thanks for the replies.
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Old 02-10-2009, 10:58 AM   #8
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An odd question


Do you know how many watts the dimmer is rated for?

Unless the dimmer is rated otherwise, it should be used only for lights.

If the dimmer came with rippled or finned trim plates, you must use those. They help dissipate heat.
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Old 02-10-2009, 11:07 AM   #9
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An odd question


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Originally Posted by 2long4u View Post
I was wrong. I did connect everything correct. I still don't know why the CFL's were flickering, but I did end up taking out the transmitter.
I took out the dimmer and will be putting that on a some 12v lighting that I have.
I will be replacing the regular bulbs in the bathroom to some decorative CFL's. Hopefully that will get rid of some of the hear they produce.
Thanks for the replies.
An AC dimmer will not work with 12VDC lighting.

FW
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Old 02-11-2009, 08:52 PM   #10
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An odd question


The dimmer was rated for 600w I had 480w running through it but now I only have 112w with the cfl's they take a little while to warm up but the savings are worth it.

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An AC dimmer will not work with 12VDC lighting.

FW
I've never had a problem using a 110v dimmer with 12v lighting before. You wire it in before the transformer.
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Old 02-11-2009, 11:22 PM   #11
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An odd question


Quote:
Originally Posted by 2long4u View Post
The dimmer was rated for 600w I had 480w running through it but now I only have 112w with the cfl's they take a little while to warm up but the savings are worth it.



I've never had a problem using a 110v dimmer with 12v lighting before. You wire it in before the transformer.
Not a great idea to control a transformer with a dimmer, unless the dimmer and transformer are made for it.
For one thing, most dinners state resistive or incandescent load only. Using them on anything else can cause them to malfunction and to overheat.

Most dimmers are Triac controlled devices, which do not let through the entire sine wave. The closest to that is full on, and even it is not a true sine wave.
Becuse the sine wave gets chopped off at the beginning, you have a very sharp rise on the pulse, something which transformers do not tolerate all that well.
The transformer may overheat, or it may just not give you the efficiency, or the output you would expect.

But I suppose that if all the transformer is powering is lighting, it doesn't really matter all that much.
If it works, use it.

FW

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