I have a shop full of 4′ fluorescent fixtures. Most of them are magnetic ballast / low temperature and use T12 bulbs. They were about $25 each and are about 5 years old.
Recently picked up 2 more fixtures in the same price range. These 2 fixtures are electronic ballast / low temperature and rated to use T-12 or T-8 bulbs!
So is it ok to use T8 bulbs in my older magnetic ballast fixtures?
The T12 = 40 watts, and the T8 = 32 watts.
Any help guys?
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Replies
Will the T-8 pins fit into the T-12 tombstones (sockets)?
Edited 7/28/2008 10:45 am by kenhill3
No problem. The 8's (1" diameter) will fit the 12 tombstone (1-1/2" diameter) but the 12's may not fit the 8 tombstone on the newer fixtures. There is not enough clearance before you hit the housing. All of the 4ft fixtures should have the same bi-pin connection on the ends of the tubes. You can even mix and match the 8's and 12's in the same fixture with no problems.
CC,
I'll give it a try tonight. A T12 next to a T8 in the same fixture. Just to see what I can see, at least it doesn't look like I could do any harm.
Dave had some good info about not burning as bright or as long.......
The pins will fit just fine, but the older magnetic ballast may not be enough to light the T-8 bulb to 100%, and you may (will) see the 60 Hz flicker in the them more.
You will also find out that the T-8 won't have as long a life with the magnetic ballast.
T-10s are the normal bulb switch out for energy saving w/o changing the old magnetic ballast.
Dave,
interesting about the Ballast. I took the Ballast part number of the newer lights and tried to do a search / cross reference with no luck. I would change out the magnetic ballast to the electronic as the old one's burn out, maybe not even worth the $$$
So if the T8's won't burn as bright or long in the old magnetic ballast,
Then is it not also a compromise ( by the manufacture ) to run a T12 in the newer electronic ballast fixture??
Thanks, Bill
I have not tried a T12 in an electronic ballast, so don't know, but if the fixture was rated for them to start with , you are probably ok.
My BIL was sold a box of T8 bulbs by a guy at Lowes. He was told they would save him 30% + in energy cost. He installed them in standard 4' fixtures with magnetic ballast. Next thing you know I'm getting a call asking why all his lights are dim and flickering. Has to be some electrical problem, right. Nope, it was the T8 bulbs and electronic ballast combination. He replace all the T8s with new T12s and everything returned to normal. I got a case of T8s that work just fine with my electronic ballast in the shop.
Over the past 7 years we have changed from T12 to T10 in the office complex where I am a maint. tech.. In the last two years we have started the conversion to electronic ballast and T8 bulbs. I would hazard to guess that we have changed over 500 to 600 fixture thus far, if not more. By the time we are finished we will have reduced our lighting load by at least 30%.
Look right on the ballast. They indicate what they are for.IIRC, at least some of the electronic ons say both T8 and T12's.And look at Lowes and HD. They should have electronic ballast..
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
He wants to know if his old ballasts would work with T8 bulbs. They won't have anything on them saying if they work with T8if they are old. My experience is the T8 bulbs don't work right with the old mag ballasts. Dim, flickers, and swirling light output.And the new ballasts usually cost as much as a whole new fixture around here, so I think the OP wants to not go that route.
T8 lamps on a T12 ballast will result in short lamp life, change the ballasts or use what lamps the ballast is designed to operate.
Deadman1,
Thanks, this is the info I'm looking for. Any chance you can share a brand or part number?
Markh,
Yes I would rather replace ballast as they go bad than the whole fixture. It would be a shame to throw all that metal in the scrap pile ( about 20 fixtures ), all depends on cost I guess.
Bill Hartman,
I did look at the electronic ballast. The only info on them was a brand name and a part number. ( think Home cheap-o ). I tried doing a search on the net with no luck. I'll have to get out and do a foot search <GG>
Dave R,
I never heard of T10's. Are they an industrial / commercial type of bulb?
Thanks guys!
If you look at the replacement ballasts closely, they all have a diagram or table telling you how many lamps of what type they work with.Problem is, replacement ballasts are more expensive than the whole fixtures.
It is an ironic habit of human beings to run faster when we have lost our way. --Rollo May
I have 10 of the Home Depo electronic light fixtures with t-8's, and am now at a 40% failure rate after 14 months of use!!! I have 2 spares and after looking at the boxes no warranty what so ever is claimed. I have verified it is not the bulbs. Its the fixtures / ballasts going out. They worked great starting up in the cold. But my half dozen magnetic fixtures that are 7 years old are still going without a failure. They start slow in the cold but ended up being way better than the electronic ones.
I have 10 of the Home Depo electronic light fixtures with t-8's
There is your problem. HD fixtures are junk.
We started replacing magnetic ballast in our commercial office building over two years ago. Now well over 600 e-ballst in service and we have had to replace only one of the new ballast since we started. That one got sent back to the vendor, since we write the install date on each ballast.
Ya gets whats ya pay for.
We purchase electronic ballast in larger quantities than most HOs would, so we get a price break, but ant electric supply house should have what he needs for $20 or less.
I think we pay about $14 each fot Triad universal electronic ballast 120/277 volt.
HD and Lowes are way over the to high on thier electronic ballast. Something like $25 each, which puts them right up there with the cost of thier el-cheapo two bulb shop lights. I put 10 two bulb fixtures with e-ballast and T8 bulbs in my wifes' kennel building for around $300 from my lighting equipment supplier.
Why are you shouting?
BruceT
Shouting?
sorry, didn't realize I was?
Edited 7/31/2008 5:57 am ET by 43Billh
Hey, sorry for the slow reply...kept forgetting to look!
I'm using Sylvania ballasts, either 2-t8 or 4-t8 for 2 or 3 and 4 bulb fixtures respectively. My local sparky supply carries them, but more often than not I grab a couple at Home Cheapo when I'm there.
Cool, thanks for getting back to me!
I'm actually stopping at home-cheapo after work for a scratch and sniff. This particular store is pretty bad, but I'll check it out. At least now I have an idea what to look for.
Bill
We see this all the time...the only replacement ballasts I stock/install are electronic, and they'll run T8 or T12s. A T8 bulb on a T12 magnetic ballast will flicker and die, a T12bulb on a t8 ballast will be fine, but might not physically fit in the troffer.
The two lamps are designed to use different ballasts. Using the wrong combination is, at best, a sure way to burn up the ballast quickly, and get poor light from the bulb.
Bite the bullet, and replace the ballasts at the same time. Or, if your fixtures are the cheap ones without replaceable ballasts, replace the entire fixture.
You won't be disappointed.
A 'normal' fluorescent 'blinks' 60 times a second. The T-5's, with the proper ballasts, blink thousands of times a second. This means a much better quality of light, especially around moving machinery.
The T-5's are not only brighter, the light is whiter and colors are better seen.
T-5's, again with the right ballasts, work much better in colder temperatures.
Finally, the electronic ballasts don't hum at all.
renosteinke'
we have the T5's here at work, and they shore are bright!
I'll bet they aren't cheap at the retail level
I've heard that the T-5's aren't to the point in development where they work well in lower temps. Any light on this? LOL.
Don't know about the temp issue, but the last batch of t-5 I was involved with, used more power than t-8. The t-5 we used can be switched from high to low, but it seems they are always on high.
Between the fixture cost, and the labour, the savings from t-12 to t-5 based on a 10 hour day 5 days a week, the payback was about 40 years.
In converting an office from T-12 to T-8, the current drawn by the lighting panel was measured afterward at about 62% of the the 'before' measurement. The new lights were also brighter .... three T-8's are comparable to 4 T-12's ... and the light was of a noticeably better quality. T-5's are another beast altogether. They are an enormous improvement over the metal halide fixtures you see in many industrial settings ... but that's a bit beyond this forum. Regular T-12's seem to start having problems around 40F. I've seen T-8's perform well at 20F, though it takes a good fifteen minutes to reach full brightness. I have seen T-5's operate - again, with a longer delay to full-bright - just fine in zero degree weather. You WILL notice more heat from these new bulbs, than from the old ones.
"three T-8's are comparable to 4 T-12's ... and the light was of a noticeably better quality."That is not because of the T-8's are better, but is because those specfic T-12 where poor light quality.All of the T-8 use the rare earth tri-phousruous and they have CRI's of 77-80.The T-12 cool white & warm whites have CRI's of arount 60. But the rare earth tri-phousrouses are in the low 80's. And there are some that are well into the 90's..
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
I don't care if they used pixie dust and had a shaman sacrifice a goat .... Fluo lights have certainly come a long way!
Agree on 12 to 8 in savings. But translate the percentage into actual dollars.
The heat issue is interesting. Smaller ballasts should mean less heat, so how does that affect the heating and cooling loads.
Lots of ripple effects.
I never associated size with heat. In any event, what I meant was that the bulbs are noticeably hotter than the older T-12's. I'll leave the 'why' to some bored budding scientist out there. What kind of money you'll save depends entirely on how much electricity you're using for lighting. Yet, there is no denying the significant savings .... we're not talking a few percentage points here - reducing your power needs by a third is a lot more that I ever would have expected. Even if there were no power savings, I recommend the switch simply because the lighting is so much better. Sure, there are attempts to 'measure' light quality.... light temperature, color temperature, "CRI,' etc .... but all those things are but attempts to put a ruler on what our eyes tell us. It's a very real difference, though, and one that will make you wonder how you ever got along without the new lights.
I do maintainance on a 1927 office building (side job for the last 14 years). We had all the magnetic ballast/T-12 fixtures retrofitted with electronic/T-8 about 5 years ago. The power company paid HALF of the approx. $20,000 total cost, and IIRC the building owners' payback from the energy savings was about 5-6 years. Good deal if ya ask me.
To put it in perspective ... You ought to be able to get the parts to make a change-over for about $30. Four T-12's on two ballasts probably draw about 1.5 amps. Four T-8's on one ballast probably draw 9/10's of an amp. Let's assume $0.14/ kwh for the electric rate. Depending upon your other assumptions, this means you'll cover your parts cost in one year. Then, figure a second year to cover the labor - though that can be eliminated as a factor, if you convert as the old ballasts fail.
>>Sure, there are attempts to 'measure' light quality.... light temperature, color temperature, "CRI,' etc .... but all those things are but attempts to put a ruler on what our eyes tell us. It's a very real difference, though, and one that will make you wonder how you ever got along without the new lights.
We converted one whole department in our building a few years ago. Used one of those light meters to check the lumins at each work staion before and after the retrofit.
We ended up with 20% more light than with the old T12/magnetic ballast combination, and both the older T12 and the newer T8s were rated at the same color temperature. Energy saving was, as you said, around 33%.
The T8 bulbs do get warmer than the T12s, but in our case that is somewhat of a plus durring the heating season. Our building HVAC system load was originaly calculated with the heat from the old magnetic ballast figured into it, as well as the body heat of each individual working there. Over the years, as we downsized, we lost almost 30% of the bodies that were figured in the heat load side of the calculation. The ballast replacement also reduces the heat load because the e-ballast do not have a lower heat output than the magnetic ballast. With the warmer T8 bulbs the net load is about the same.
We just need more bodies to keep the place warm durring the winter (g).
Has anyone else found that the electronic ballasts and T-8's make noise on the radio stations? I have some magnetic T-12's that don't bother the stereo but the more T-8's I turn on the worse it gets.
The fixtures are all grounded, all lighting is off the same breaker, and the FM antenna is located in the attic some 25+ feet away.