Converting dimmed fluorescents to LED

ryderimmel

Member
Location
vancouver wa
Occupation
Journeyman
Can you install ballast compatible LED tubes on a dimmed fluorescent ballast and have the dimming function still work with the existing fluorescent dimmer switch? I think the easiest way to convert this space is to rewire all fixtures to ballast bypass and replace the switches with LED dimmers, but if I could just replace the tubes that would save a lot of time and $$$.

Thanks all
Ryder
 

synchro

Senior Member
Location
Chicago, IL
Occupation
EE
Can you install ballast compatible LED tubes on a dimmed fluorescent ballast and have the dimming function still work with the existing fluorescent dimmer switch?
Could you try this on one fixture to check whether it'll work OK before going ahead with all of them? If it works then it's not a 100% guarantee that it'll work with all fixtures re-lamped, but if it doesn't work then it's a non-brainer to go do something else (e.g., try a different brand of LED tube or go ahead with ballast bypass).

I think a ballast bypass is the best in the long run. And if any problem comes up it should be easier to diagnose with one less component to worry about.
 

brantmacga

Señor Member
Location
Georgia
Occupation
Electrical Monke
Keystone makes an LED tube designed to work with a dimmable ballast. I can’t remember the part number; if you call tech support they’ll provide it. I know the lamps that end in “FDIM” are ballast-bypass type designed for forward phase dimming, and “VDIM” is 0-10.

Edit …. I think this is it. I was on the phone with them a couple of weeks ago and pretty sure tech told me these are ballast dimmable. Call and verify.


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Last edited:

brantmacga

Señor Member
Location
Georgia
Occupation
Electrical Monke
Are the existing fluorescent dimmers 0-10V or line voltage dimmers?

That’s a good question to OP.

If they’re 0-10v, I’d consider using the keystone 0-10v ballast bypass type. One end of the lamp is line voltage, opposite end you connect dimming wires to the keystone.


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Flicker Index

Senior Member
Location
Pac NW
Occupation
Lights
Fluorescent dimming ballasts are programmed rapid start, or rapid start, depending on vintage. Most drop-in lamps are not compatible. You'll have to contact retrofit lamp sales rep with ballast model #.
 
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