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Light dimmer/fluorescent lite question

Efland, NC(Zone 7a)

Quick question, folks....

I've put light dimmer switches on the wall for incandescent lights before but was wondering if anyone has ever used them to dim a fluorescent light before.

Would there be a big mal-foogerty? Would it mess up the light? (Those fluorescent lights need power to light the gas in them and didn't know if the dimmer switch would be safe.)

The reason I ask is I have two 4 ft shop lights on the ceiling in my shoffice and sometimes the glare is too much. I was thinking of putting in a dimmer switch so I can reduce the light (and the glare).

Does this sound feasible, or am I gonna mess something up?


Tellico Plains, TN(Zone 7b)

Hope you find answers here Shoe =)

This message was edited Mar 13, 2004 8:01 PM

Lexington, NC(Zone 7a)

Shoe, I have never heard of dimming flourescents and I do know which wire not to grab. Would think once you lowered the power the lights would just start flickering, then go out. You have aroused my curiosiity and will see what I can find out about it.

Lexington, NC(Zone 7a)

Guess I was mistaken. The following is taken out of context from some kind of research paper.
According to my previous research, we can only reduce light
levels emitted by the fluorescent tubes by up to 40% using a dimmer
switch--if we attempt to lower the levels any further the lights
will flicker.

It didn't tell how to install a dimmer switch.

Efland, NC(Zone 7a)

Okay dokey....thanks Sparks, I wondered what would happen if I used a dimmer on them. So...I could dim them to a certain point, and when they start flickering then give them a tad more power, maybe?

Scooter, thanks for the links. One of them said only certain kinds of fluorescents can be dimmed, I'm sure I don't have that special kind.

Thanks folks!

Rethymno, Crete, Greece(Zone 10b)

Hi Horseshoe, I was wondering if you can get your job done by adding aluminium blocks under your lights, or by switching to lower watt lamps. Aluminium blocks are made of light aluminium sheet, they come in a trellis-like or honey-comb like pattern and block oblique rays allowing only the vertical ones to reach their target - I am not sure if you can find them on their own or you have to pay for new lights altogether.


Efland, NC(Zone 7a)

Ohhh...I've seen things like that in offices and such. Good idea, Dimitri. I'll have to keep an eye out for something like that.

Western, PA(Zone 6a)

I remember back in wiring classes the instructor saying DON'T use a dimmer switch on a fluorescent light. We didn't ask why. We just don't.

The link to Cole Hardware says. a special fixture and compatible dimming control are necessary.

The filtering idea sounds best.

Good luck, and let us know what you did.

Northport, ME(Zone 5b)

Horseshoe, lately I've been hearing about how you and Red Green may be... Is some duct tape in order?

northeast, IL(Zone 5a)

There are dimming fluorescent ballasts. I'm not sure how readily available they are. Sylvania makes some, I'm not sure who else. I work for Sylvania in R&D on electronic ballasts for fluorescent lighting. If there is anything you need to know I will try to find the answers. We make some that will dim down to 10%, no flickering whatsoever.

Efland, NC(Zone 7a)

Howdy Folks....just now getting back to this thread.

I never did add the dimmer switch...when I got it out of my supply box I read the back, "To prevent over-heating and chance of fire do not use with fluorescent lights or motored appliances". So, that settled that problem, eh?

Maybe it was just the dimmer switch I had. Maybe there are others that CAN be used with fluorescents?

Momcat, it sounds like it is not the light so much as it is the ballast? I better check those out at Lowes or Home Depot next time and see what they offer there. Thanks!

northeast, IL(Zone 5a)

Yes, Shoe, it is the ballast that makes it dimable. I know we are making more and more dimming ballasts. You can get some fluorescents to dim somewhat by lowering the input voltage, if you have that capability, but once they get below 75 to 80 volts input on a ballast made to operate at 120V, the lamps will generally start to flicker. The dimmer switches for fluorescents are, I believe, different from your standard dimmer switches.

Efland, NC(Zone 7a)

Ohhhh...okay. I understand. They can be dimmed, but need proper dimmers.

I'll be sure to check out the Sylvania brands. Thanks! Will holler back and let ya know what I can find on the "open market".

Spokane, WA

umm.... shoe?

heres my two cents....

one cent. get a dimmer switch

two cent... put it in, n get some tape...

three cent... mark on the tape where the lites begin to flicker....

four cent... DON'T GO THERE!!

(ok, thats more than two cents)



comment: all teh research in the world won't do ya no good till ya use it. meaning, put in the dang switch n find out... lol :D

Efland, NC(Zone 7a)

Hah! Thanks SO1...makes good sense to me!

Glendale, UT(Zone 5a)

I tried it, and had to take the dimmer switch back out and replace the ballast.

Efland, NC(Zone 7a)

Hmmm...sorry you blew out your ballast, Michael.

I finally took a good look at this dimmer switch...had to use a magnifying glass to read the back. "Not for use on fluorescent fixtures". Guess that settles that, eh?

Glendale, UT(Zone 5a)

I should have used a magnifying glass also ,because I still don't know if anything was written on the back of mine.

Glassboro, NJ(Zone 7a)

To dim a fluorescent you need a combination of a special dimmable ballast with a fluorescent dimmer. This is an expensive combination. You could rewire the fixtures so you could control each of the bulbs in a fixture seperately and this would allow you to cut the light output down much more easily.

Ken & Sue in Glassboro, NJ

Efland, NC(Zone 7a)

Thanks morrowsmowers,

Since this first post I found a dimmer switch that was made for fluorescent lights. Not sure what the difference is. However, it was expensive (for me) so I just decided to turn off the overhead lights when they are too irritating and use table lamps.

By the way, just noticed your joining date...please accept a big hearty


Hope to see you around the site!


Glassboro, NJ(Zone 7a)

The fluorescent dimming ballast is a special package of circuits that is made to work with the dimming ballast that you must install in the fixture. You need both of them used together to get fluorescents to dim properly -- and then you can only get so much dimming before the light becomes useless and then just plain goes out. There are ways to "stage" lights in a fluorescent fixture to give lesser or more light as needed that would be much easier than dimming if you don't really need the dimming feature.

Ken & Sue in Glassboro, NJ

Precipice Valley, BC(Zone 2a)

Shoe, we have one fluorescent fixture that we can raise or lower to reduce the light; and another for which I have a second cover that I tinted. Not as easy as a dimmer switch but cheepcheepcheep!

Efland, NC(Zone 7a)

Hehehe...I luv 'cheep cheep cheep'! Thanks chilko! (Great idea to tint the cover...that just may be what I need to do!)

And again, thanks ken and sue...I logged your info into my memory bank!

Be seeing you both around the site! Great place to hang out, eh?!

JERSEY. C. I., United Kingdom

we, over here in the UK cannot use dimmer switches for tube lighting , only for bulb lighting

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