T8 Retrofits

jmellc

Senior Member
Location
Central NC
Going this week to look over a job. 20 some flourescent lights to change to T8. Office manager says they are a 1x4 fixture, flush with ceiling. Insists they are not lay in troughers. I think I've seen some of these but will have to look 1st hand. She also didn't know how many bulbs, etc.

Are T8 retro kits available for all styles of flourescents now?

Thanks for any feedback.
 

fmtjfw

Senior Member
Tombstones are the same, tombstone wiring may need to change. With T8 and electronic ballasts both connections in the tombstone are to be connected together. Older T12s may have had different wires to each side of a tombstone, depending on the ballast and type of tubes.
 

jmellc

Senior Member
Location
Central NC
If these are the type of lights I'm thinking of, I'm sure they will need new tombstones too. The lights are probably 50 years old or more. I think they will be sort of a box looking fixture, 4 feet long, 1 foot wide, 6 to 8 inches deep, with side flanges. Probably nailed to joists & drywall installed around them.
 

jmellc

Senior Member
Location
Central NC
Checked out the job Fri. A number of these are what I was thinking. Old, but very high quality. Covers latch securely, open & close easily. No twisting & wobbling, latches don't bend. Sockets are even accessible with a little prying. A pleasure to see flourescents that don't come apart in my hands like a lot of the troughers made today.

I am quoting to retrofit the flush mounted lights, retrofit a few flourescent uplights over restroom mirrors and replace a few surface mount flourescent wrap fixtures. I was surprised that a fixture is cheaper than the retro kit, about $15.00.
 

jmellc

Senior Member
Location
Central NC
Still waiting to see if I get this project.

Has anyone used T8 retrofits & had any problems? I don't foresee any but want to be prepared. Sockets should be able to mount in existing brackets, ballast should have plenty of space, fixture is plenty wide & long.
 

fmtjfw

Senior Member
Still waiting to see if I get this project.

Has anyone used T8 retrofits & had any problems? I don't foresee any but want to be prepared. Sockets should be able to mount in existing brackets, ballast should have plenty of space, fixture is plenty wide & long.
Done hundreds no problems. The only thing to look out for is that both pins on each tombstone are to be wired together. Some older T12 ballasts/bulbs had different wires to each side of the tombstone.
 

BullsnPyrs

Senior Member
Done hundreds no problems. The only thing to look out for is that both pins on each tombstone are to be wired together. Some older T12 ballasts/bulbs had different wires to each side of the tombstone.
Not true in all cases, program start ballasts do not use a shunted tombstone. these are the ballasts specifeied when putting t8 on an occupancy sensor to prolong lamp life.
 

fmtjfw

Senior Member
Cool.

Cool.

Not true in all cases, program start ballasts do not use a shunted tombstone. these are the ballasts specifeied when putting t8 on an occupancy sensor to prolong lamp life.
You learn something new every day. Thanks for the info. Where I worked, schools, the rooms were generally occupied all day, so the lights stayed on. I can see with occupancy sensors and lots of starts, maximizing the number of starts with a lamp makes sense.
 

Electric-Light

Senior Member
When you shunt the sockets for instant start use, the shunting needs to be done as close as realistically possible to socket or lamp life will suffer.

You learn something new every day. Thanks for the info. Where I worked, schools, the rooms were generally occupied all day, so the lights stayed on. I can see with occupancy sensors and lots of starts, maximizing the number of starts with a lamp makes sense.
Some PRS are wired the same as traditional F40T12. Some are not. (for example, heaters wired in series... or center wire connected back to ballast via 3 wires instead of 2 wires)
 

jmellc

Senior Member
Location
Central NC
I wasn't thinking of program start ballasts & the quote from supplier did not mention them. Should I check and be sure or do they only provide those if specified?
 

Electric-Light

Senior Member
I wasn't thinking of program start ballasts & the quote from supplier did not mention them. Should I check and be sure or do they only provide those if specified?
Program start only represents a few percent of all T8s installed. Unless otherwise specified, they're most likely instant start.
If specified, the ballast usually costs substantially more.

If they're four lamp fixtures, they're probably two sets of two as four lamp F40T12 ballasts were almost unheard of.

For T8 retrofit, the common practice is to use a single unit four lamp ballast unless existing setup is wired for, and you need to retain the ability to switch between 2 and 4 lamps. For four lamps, one side needs to have all four sockets and all 8 pins connected to one wire on ballast.
The two pins on sockets on other side are individually jumpered and connected to corresponding leads. There are five wires that go to lamps on a 4 lamp ballast, common, and 1,2,3,4.

The only situations involving unusual and complex wiring is when you're dealing with 3 or 4 lamp programmed start , dimming and some step dimming ballasts.
 
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stevebea

Senior Member
Location
Southeastern PA
Going this week to look over a job. 20 some flourescent lights to change to T8. Office manager says they are a 1x4 fixture, flush with ceiling. Insists they are not lay in troughers. I think I've seen some of these but will have to look 1st hand. She also didn't know how many bulbs, etc.

Are T8 retro kits available for all styles of flourescents now?

Thanks for any feedback.
I dont know of a retro kit for 1x4's. Last week I checked with a supplier.... Columbia, Simkar, Williams, none of them make a retro kit for a 1x4.
 
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