# fluorescent light questions



## JesseTutt (Aug 15, 2012)

I use 4' dual tube fluorescent lights in my shop. They are 40 watt and have the two prongs on each end. As I prepare to replace the burnt out tubes, several questions popped into my mind. I am hoping that you can help me understand what is going on.

Of the 12 fixtures in the shop 4 never give me any problems. The remaining have problems. Some have just stopped working.

Others will work for some time and then stop for a while and then start again. I would think thermal problem but, sometimes a fixture will work all day every day for a week and then start / stop working at random periods for a few days and then work for a long time.

Many that are not working will start if I wiggle the tubes. I might have to remove the tube and put it back in. I am wondering if I have a dirty contact between the tube and the socket.

Some tubes will develop a black section along one, or both, ends. I always thought this was an indication that the tube was about to fail, but I have had tubes with black work all summer with no problems. Other fixtures having problems may or may not have tubes with black. There does not seem to be any correlation between tubes with black and fixtures not working.

Any insights you have would be appreciated.


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## grfrazee (Jul 17, 2012)

How long have you had the fixtures? It's possible the ballasts are burning out.


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## MedicKen (Dec 2, 2008)

The fixtures that are not working sound like a ballast problem. The ballast is the starter for the fixture and is located under the panel between the bulbs. If these are older lights its probably time to replace the ballast. Do you get any humming from them? The older ballasts are know for an annoying hum. They are easily replaced. When you go to get new bulbs look for the highest color rating you can find. They will be closer to natural light as opposed to the cool white bulb. IIRC the bulbs you want are C95 but I could be wrong on the number. There should be a number printed on the bulb and or box stating the color rendition. The higher the number the closer it is to natural light


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## ClintSearl (Dec 8, 2011)

You need new ballasts.


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## JTuretsky (Mar 2, 2011)

When the lamps flicker or take a long time to turn on, the current is either insufficient or not constant. This could mean their is an issue with your ballast or connections, but its related to the current. Fluorescent s have large ballasts in the fixtures to tune the electricity to the proper level, check the connections there, and the connection to the fixture were the pins contact. Also, maybe cleaning "socket" is not a bad idea.


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## Grandpa (Jan 28, 2011)

I vote ballasts also. The black ends usually indicate the bulbs are getting weak. If the ballast is getting hot it might not be able to send the electric flow through the tube. Replace the ballast and the problem should go away. Go ahead and change to the electronic ballast and energy effecient bulbs while you are doing this. This is a job a homeowner should be able to do if he or she is a little bit handy. Be sure to unplug the unit or turn the breaker off. You currently have the regular flourescent unit that operate best in temperatures above freezing. Cold weather units have only one contact on the end and cost a *BUNCH* more. The will fire in below freezing temperatures and they work longer in those conditions if you have those.


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## HorizontalMike (Jun 3, 2010)

In addition to the ballasts mentioned by many, I would AVOID the use of any lower wattage "Econo-bulbs" as these always gave me fits when the temperatures dropped. They do not start in lower temps. Buy the highest available wattage available. You might even try moving to higher wattage ballasts as well. I have the old T-12 8ft dual fixtures and when I got rid of the 40w and replaced with 75w my issues went away.


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## Charlie5791 (Feb 21, 2012)

I started replacing a lot of flourescents with 6 inch can lights fitted with LED bulbs. 
Search for ECO-575L. Prices can vary quite a bit, but the 6 inch can fixtures are cheap and these go right into a standard Halo 6 inch can.

There's an expense involved to be sure, but if you are replacing ballasts and/or fixtures, it's worth a look. I just redid my hole kitchen with them. I've been putting them in the basement, the garage, the shop. They start immediately when it's cold (it gets cold here). They are cheap cheap cheap to run. They won't burn out for about 20 years hehehe. And I like the LIGHT better than any of the flourescents. It's more natural. Kinda like working outside.

Just thought I'd toss it out there. This brand is made by Cree Lighting and Cree does LED lighting right. (No I have absolutely no connection to the company)


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## MJCD (Nov 28, 2011)

The 40-watt bulbs are probably the older T-12s, which are fine - the 'eco-bulbs' are T-8s, and they'd be the 32-watt you see in stores. The T-8s ballasts tend to be quieter in cold weather. I agree with HorizontalMike - no one has gone blind using too much light in the shop - mine could be used for a landing strip.

MJCD


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## HorizontalMike (Jun 3, 2010)

MJCD,
Oops, I probably mis-spoke. The lower wattage were probably 8ft 60w vs the higher 75w. All I remember is the lack of cold starting and that HD phased them out because they were actually NOT economical according to the newer standards/regulations.


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## JesseTutt (Aug 15, 2012)

Update: for the fixtures that were not working, I removed the bulbs and used 320 grit sandpaper to clean the contacts. This fixed one of the bulbs. For the rest I put new bulbs in and they are now working.

The fixtures are the low cost ones from Home Depot.

Some fixtures I have seen in the past have the large transformer (?) inside of the fixture and a small can that plugs in and turns.


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## BillWhite (Jul 23, 2007)

Sounds like you have a fix, but T-8s are what I have. I've replaced 5 of 8 ballasts (at Lowe's cost). So far, no more probs. The Chinese electricals…..........................Oh well.
You want egg roll with you (no typo) lights? Shut up and eat it!!!!
Bill


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## brtech (May 26, 2010)

My shop is mostly lit with those basic $20 dual 4' shop lights from the big box.

I had my garage redone this year and, on the advice of the contractor, we put two 8' HO fixtures in. I was BLOWN AWAY by how much light these suckers put out. It's BRIGHT, really bright. They come on right away, no flicker, no hum. Definitely worth the price difference, which is considerable. I think you are close to $100 for a two light 8' with HOs. They sell the fixture without the bulbs, unlike the 4' shop lights.

I'll be redoing the lighting in the shop, right after I finish the shelves, the blanket chest, build the new bench, get the jointer back in business, ....


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## longgone (May 5, 2009)

I have been replacing mine with the newer lights that use the electronic ballasts and have been repolacing the bulbs with the daylight bulbs…Their light is much better and allow me to see more details. No problems with these as I had with the older flourescents.


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## WoodKutter (Nov 27, 2008)

Jesse, 
The light fixtures you have are quite old. The T12 ballasts in them generate a lot of heat. The black ends of the bulbs are caused by the heat generated in the fluctuations of current caused by the old ballasts. It will cause the bulbs to burn out prematurely. The fixtures on which you moved the bulbs or took out and put back in for them to work have weak ballasts. The ballasts are not putting out enough to fire up the bulbs. By moving them, you cause an arc at the lampend which spikes the current slightly. Once the bulb lights up, it takes very little to keep it lit. The fixtures which come on and go off sporadically have ballasts which are dying. They over heat, shut down, cool off, come back on. They may stay off for days, then one day start working again for a few days. Sometimes they strobe and drive you crazy.

The problem you will have with updating those old fixtures to T8 ballasts and bulbs is that the wiring colors are different. The T12 ballasts will have 2 yellow wires, 2 blue wires and 2 red wires. The T8 ballast will have 1 red wire and 2 blue wires. Also you may have to change the wiring in the fixture. Some T12 40watt ballasts are wired in series and some are wired in parallel. It is not hard to do but you need someone who knows how. A lot of times the wire insulation is brittle and will break when moved. If you know someone who can show you what to do on one fixture, you can probably do the rest yourself.

My advise would be to replace the entire fixture with a new one. Often times you can buy a whole fixture for about the same or less than the cost of a ballast. The ballast went out in my kitchen light and I purchased a new fixture for about $10 dollars more than the ballast by itself. And it was a nicer light fixture than the one I had.

Good Luck, 
Gary


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## teejk (Jan 19, 2011)

I think T12's are going to be outlawed soon according to the newsletter I got from my elec CO OP. I started using T8's (32w) years ago (0F start, seem to last much longer and the light output seems to be as good as the old T12s). But back to the question…T12 replacement ballasts will cost more than the fixture! And just something I heard…electronic ballast failure is often related to poor grounding of the fixture.


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## Knothead62 (Apr 17, 2010)

Check on the price of ballasts. I worked at Lowe's in the electrical dept and it was more cost effective to replace the whole light fixture.


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## HorizontalMike (Jun 3, 2010)

teejk,
Unless you have something new to share, I was told that the old T12 "High Output" (75w) would remain in production. This is the lighting I have and I would appreciate any links you might be able to share on this.


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## klassenl (Feb 13, 2011)

JesseTutt wrote "Of the 12 fixtures in the shop 4 never give me any problems. The remaining have problems. Some have just stopped working.

Others will work for some time and then stop for a while and then start again. I would think thermal problem but, sometimes a fixture will work all day every day for a week and then start / stop working at random periods for a few days and then work for a long time.

Some tubes will develop a black section along one, or both, ends. I always thought this was an indication that the tube was about to fail, but I have had tubes with black work all summer with no problems. Other fixtures having problems may or may not have tubes with black. There does not seem to be any correlation between tubes with black and fixtures not working."

Speaking as an electrician with many hours working on fluorescent lights…......this is just how they are, especially the old T12's. If I had the answers to these questions I would be a very rich man.


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## mojapitt (Dec 31, 2011)

T12 bulbs are being discontinued by federal mandate. Might as well replace them with T8. LED bulbs are the way to go in cold shops. However, they are only slightly more efficient than T8's. Since they are significantly more expensive it's hard to justify them.

Note; don't just put T8's in any T12 fixture. The older ones aren't designed for T8s. Either they won't work or they will burn blbs out. Bite the bullet and put in proper fixtures.


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## HorizontalMike (Jun 3, 2010)

Sorry Monte, but with 6 T12 75w double 8ft'rs in my shop and short on funds, these are not going to be replaced until they completely die. I have seen the lower wattage(60w) T12 bulbs disappear from HD and when queried, the HD folks told me the "High Output" were unaffected by the new standards and that those bulbs would still be available.

How long those "High Output" bulbs will continue to be available is what I am trying to nail down. *If you have any references as to when they too will be discontinued then please post those links.* I would like to know because I will be trying to time a final purchase of these 75w T12 8ft'rs for backup. After all, my original bulbs are still going strong after 8-9yrs. I have only replaced 2 of the 12 bulbs during that time, and that was because they were of the "Low Output" 60w variety.


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## donbee (Feb 7, 2009)

I have been slowly (as I can find the time and energy) revamping my four foot fluorescent fixtures.
I pull them down and gut the old electricals completely.
Then I line the reflector with a mirror mylar film to improve output. (White paint absorbs about half the light it receives.)
Then I mount four conventional lamp sockets in the horizontal position and wire them straight to the switch and 120vac.
I use CFL lamps with a full spectrum output.
The fixtures use only 60% of the current they used to take and give much nicer, brighter light.
Don


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## teejk (Jan 19, 2011)

horizontal…I did some checking and have to say it's confusing…T12's supposed to be gone as of July this year but some extensions were granted to July 2014. I didn't see any carve out for HO's so I assume they are toast in 2 years. We have Menards here and I see that they now sell fixtures that will accept either T12's or T8's.

http://cleantechnica.com/2012/07/14/another-light-bulb-deadline-looms-wheres-the-outrage/


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## teejk (Jan 19, 2011)

Don-brilliant high gloss white surfaces do make a huge difference in brightness. I have 2 banks of 12 tubes each in a 30×40 space and it's perfect. I have a 16×30 unfinished space attached with 4 tubes and you wouldn't even know there was a light in there.


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## DrDirt (Feb 26, 2008)

Suppose it is a good time to weigh-in on what is happening.
First Teejk - the extension mentioned in your link is ONLY for T8- and has no T12 impact.
The law that went into effect, set July 14, 2012 as the date to stop manufacture and import.
many companies cranked up production and stockpiled, so there are products on the shelves, but no more are being made.

The Department of Energy wants to eliminate T12 from the market. They set efficiency standards (lumens per watt) much like Miles per gallon.

They are ONLY allowed to regulate based on the efficiency and not on the shape of the bulb. e.g. They cannot just say "T12 is no longer allowed" instead they set a Lumen per Watt Standard that the T12 is not able to reach.

So what is left right now are what are "Exempt" T12 products. T12 lamps that have very high color rendering (87 CRI or higher) are not regulated.
The lamps you have now are probably Cool WHite… and those are Not availble any longer.
But there will be Cool white Deluxe "CWX" or "CWS" 
As a result - there are now families of Exempt products available.
A positive note is the Exempt lamps have much better color quality
The down side is they are LESS bright.
In general the expectation is that those two facts will pretty well offset eachother, that the lamp is a little less bright, but the colors of objects under them "pop" by coparison, so it wouldn't SEEM dimmer.

To H-Mikes quesiton about the T12 HO. I think you have slimline lamps - the ones with a single fat pin on each end.
Those were 60 watts for energy savers and 75 watts regular

8 foot HO lamps are at 90 watts for the energy savers and 110 watts regular. And have a recessed base (RDC)









If you have 4 foot bipin fixtures - go to T8 for high brightness "future proofing" 
It is probably cheaper to get new fixtures than just the replacement ballast.
The T8 and T12 lamp holders (sockets) are the same but as has been mentioned, the Ballasts are different.


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## MrRon (Jul 9, 2009)

I have the same problem as you, but only when there is a lot of humidity. When there is low humidity, the problem goes away. Try to check this first before replacing ballasts or lamps. I don't know how to resolve this.


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## Kelby (Oct 19, 2011)

The cheap big box fixtures are horrible this way. When I had my electrician re-wire my shop, I had him put in some nice 8' fixtures. No buzzing, flickering, or other problems at all. Light bulbs last forever, too.

Lighting is definitely one of those areas in which you get what you pay for.


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## DrDirt (Feb 26, 2008)

To MrRon - if it is a humidity related problem - use some turtle wax on the bulbs.

When the bulbs are manufactured they are sprayed with a silicone emulsion. The purpose is to ensure that any condensation would always bead up, and not provide any conductivty on the outside of the bulb.

Best wax would likely be any of those trigger spray "wipe on wipe off" types.

Kelby - you are definitely right on the price… if you are getting a fixture off the end display from Walmart for 9 dollars, while an Advance ballast at Depot costs 18.99 you are going to see the problem.

For most folks though it is cheaper/easier to get the nice fixtures, even from Depot.

When I did my shop I got teh 8 foot fixtures that use 4 T8 bulbs as 2 rows of 2 rather than the 2 -8 foot lamp version.
As such from each (2lamp) run:
2X32 = 64 Watts delivering 5900 lumens (2950 lumens each).

so the Fixture is delivering 11,800 lumens using 128 watts

For the T12 each 8 foot (1 lamp) run is 
75 Watts delivering 6600 lumens (color is 841 so 85CRI and 4100 kelvin - cool white color but good CRI)

The fixture is delivering 13,200 lumens using 150 watts nominally.

They are both quite efficient - but the "NEW" 8 foot T12 75 Watt lamps will deliver 4500 lumens at a 90 CRI instead.
So each fixture will be in the 9-10,000 lumen output.

Also the 8 foot lamp is more than 2 times the cost of a 4 footer, and is a bigger pain to carry home.

Course I got an Armload of T8 bulbs at work for free, that had some incorrect markings….


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## HorizontalMike (Jun 3, 2010)

Looks like I need to stock pile some T12 HOs for the future. Money is real tight here for at least the next 24-months, but as I have mentioned these things have been going strong for ~8years or so. But then again the shop bulbs probably only get about 60-90 8-hour days/year, and the bulbs are rated for 10-years at 8hr/day/365. At my use rate I am not sure if or when the savings would show if I jumped into the better fixtures at this point. If I get enough spare bulbs, then I could slowly replace fixtures as the ballasts go bad but keep using the dwindling remaining T12 fixtures. I'll check out HD this weekend.

Thanks Dirt, and teejk as well.


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## PRGDesigns (Jan 25, 2012)

Lowes discontinued the HO bulbs I needed for my new 8' HO light fixtures I just bought from Lowes - closeout price - $0.15 per bulb. Yes, that is correct 15 cents. I was expecting to pay $15.00 to $20.00 a piece. Nice surprise. I bought all they had. I had so many of these HO fixtures in my former garage it was rated for surgery. No more four footers for me ever again. I cut back in my current garage, but still using the 8' HO's.


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## curliejones (Mar 12, 2012)

http://lumberjocks.com/curliejones/blog/30371
My take on shop lighting - don't invest too much in each fixture and have bulbs that are reasonably priced and will get even cheaper as they become more common with incandescents on the way out. With the low amp draw and low heat output, you can put up to two 100W CFLs in each. No ballast to go bad and cause you to replace ballast and bulbs (another $30?) in 3-5 years. Decent light in the color of your choosing, or do as some folks and blend daylight and warm white to improve color rendering.


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## DrDirt (Feb 26, 2008)

Curlie - it certainly avoids the ballast issue, but I find that I like to have more even lighting spread throughout the shop,.

So while my shop is 14X21 it has 3 8 foot and 2 4 foot fixtures to give great light, without having a big bulb that becomes akin to staring at the sun.

Don't think there is a money advantage on the product, as the Ballast in residential use is going to last 20 years. The old magnetic ballasts just kind of lasted forever


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