Why Short Lived Flourescent Tubes?

[Robert Brandt2]

My shop is a 20 x 20 garage. No windows and unpainted sheetrock ceiling, 8' high. I have a combination of 4' and 8' flourescent lights, supplemented with incandescents mounted on tools or clamped here and there. My problem is that the average life of t8's - the 4' ceiling mounted $10 fixtures - seems to be 6-8 weeks. The 8' seem to last much longer. Over the past year or so I've tried leaving all the flourescents on all the time. It doesn't seem to make any difference.

I've even changed fixtures. The 4's have all come from a big box and all have starters, not ballasts. (The last time I replaced the ballast in the 8' fixture, I decided I didn't want to do that again $$$.) On one of the 4' fixtures (that has stayed on for several years) the transformer actually melted the fixture. It almost fell out of the fixture, but by the time I discovered it, everything was cool and seemed to still be working fine - but it still burns out tubes as fast as the other units.

I'm still using "economy" grade lights, rated at 2,000 hrs. If I can't get more than several hundred hours use from these, I don't know what a "better" light would do, other than cost more. At this point, I'm not concerned about light color or temperature.

What am I missing?

Thanks,
Robert

[Dewey Torres]

Rob,
Something is wrong. I don't know what it is but something is definitely wrong. I have the same (or similar) set up and my bulbs have gone for over a year now.

In my old shop in VA, the moisture content was higher and I went through more bulbs than I do now in Colorado but I have never had them only go for 6-8 weeks.

[Ken Fitzgerald]

Robert,

I have all 4' T-8s. 44 total bulbs....11 fixtures. Haven't replaced one yet.

[glenn bradley]

Similar experience to others. I have not yet replaced a T-8 lamp. You mention $10 fixtures . . . are you running non-electronic ballasts? With lamps going out that quick you will soon pay for quality fixtures ;-)

[Robert Brandt2]

I don't think these are using ballasts at all. The only component besides the tubes is a "starter" - cylindrical, about as big around as my thumb and 1.5" long - 2 prongs. Is this an electronic ballast?

The 8' fixture has what I call a ballast - 8-9" long, about 2" square, weighs 3-4 lbs. Those aren't a problem - just expensive to replace.

[Jim O'Dell]

I think your problem is poor quality fixtures. Fluorescent lights should have a ballast. IIRC, I have seen some that had both, but I don't remember any with just the starter, but I could be wrong here. I have the 25.00 4' fixtures from HD, T8, and bulbs from businesslights dot com, and haven't had a single bulb issue. They've been up and working for about 2 years now. The 8' quad 4' bulbs are about 43.00, same brand, same place. One has a ballast that buzzes and interferes with my radio's reception, but no problems other than that.
I'd take them back and upgrade to a better fixture. Jim.

[Bill Arnold]

I have eight T8 2-bulb fixtures in the old side of my shop building that have been in use for two years with no failures. I have twelve of the same fixtures in the shop addition I built and they have been in use for about 18 months. As I recall, the fixtures cost about $30 each; bulbs are bulk-packed cool white.

[Rob Lineman]

Been a lighting designer/engineer for the last 20+ years and never heard of a problem like you describe. Almost all new T8 luminaires are electronic ballast, rapid or instant start, with the magnetic style ballast almost non-existent except in retrofit applications (not saying they are non-existant, just not used in new appications due to the Fed's energy regulations for new construction). Have read articles on some Chinese imports that are essentially junk, and anything under 15,000 hrs lamp life I would consider junk. Normal rated LL is 20,000 hrs with 2 on/off cycles per 12 hr period, but the depreciation is negligible with reasonable higher cyclic rates. Stick to quality lamps (Osram, Philips or GE) and you'll see a good return in lamp life. When you say they are rated for 2000 hrs that would send up scores of red flags to me when a standard A19 incandescent has a nominal rating of 3500 hrs. Change your luminaires, you'll save money in energy costs and obvisously lamp replacement costs. Cripes even the big box stores sell Lithonia or equal at a relitively cheap price.

[Steve Rozmiarek]

Robert, you really get what you pay for with flourescent fixtures. You need to upgrade fixtures IMHO.

[Robert Brandt2]

Well I was close on the life ..., only left off a zero! The Philips T12s - not T8 - and are rated at 20,000 hrs. The GE's at 15,000 hrs. Both last the same couple of weeks. Both have the correct size starters.

None of these 4' fixtures definitely do not have a ballast. What's the difference? (other than the obvious.)

[Rob Lineman]

Common mistake. IMHO purchase new luminaires and pitch the rest (save your lamps if you purchase new with T12 style lamps) following is a thread found and added
Does your fixture have a starter? Maybe... though probably not!

A fluorescent starter is a little gray metallic cylinder that plugs into a socket attached to the fixture's frame. Its function is to send a delayed shot of high-voltage electricity to the gas within the fluorescent bulb. The delay allows the gas to become ionized so that it can conduct electricity. Because this process is not instantaneous, the bulbs will flicker for a few seconds before lighting. Hence, a defective starter can cause either flickering or total darkness!
Most modern fluorescent fixtures do not use starters, so you might not find one if your fixture is less than 15 to 20 years old. When determining whether your fixture uses a starter, be sure to look underneath the bulbs... sometimes the bulbs have to be removed first to gain access to the starter. If you do not see a starter... they are never hidden under any covers or "trap doors"... your fixture is a modern "self-starting" type.
Starters are rated by wattage to the bulbs they will control. If you have a fixture but have misplaced the starter, write down the wattage of any of the fluorescent tubes and take that information to the hardware store, lest you be scolded by the mean clerk and sent home without supper... or a starter.
Sadly, there is no way for the home handyman to troubleshoot a starter except by replacing it. Before replacing the existing starter, though, be sure it is securely seated in the base by removing and then reinstalling it. A starter is installed by pressing it into the socket and then turning clockwise till it locks in place. To remove a starter, press in and turn counterclockwise... then withdraw the starter. You may need
If you own fluorescent fixtures that use starters, always keep a few handy for troubleshooting purposes! And don't forget to throw away used ones... most of the time it is impossible to tell the difference between a good and bad starter!

Bet you money the wattage of the lamps are not matched

[Rob Lineman]

BTW the 8 footers you mention from the description are probably magnetic ballasted. size matches others I've seen and used and yes they're expensive to replace (better to just replace the light)

[Rollie Meyers]

If your fixtures have starters you cannot use T8 lamps if one expects decent lamp life, starters were used in the dark ages and still quite common in Europe, and were used w/ lamps not compatable w/ T8 lamps of the type used commonly today read the ballast label, it will state what lamps it is built to be used with. T12 lamps cannot be used w/ a T8 ballast or T8's can't be used w/ a T12 ballast, short lamp life/ ballast damage will result....

[Phil Thien]

I know incandescent bulb life suffers greatly if used at higher line voltages than rated.

Is it possible that your line voltage is a little high?

With an electronic ballast I wouldn't think that would be a problem, but you never know.

[Robert Brandt2]

Follow Up -

I replaced all of the "cheap" big box 2 tube T-12 fixtures with 4 tube T-8 trofflers that came out of an office building renovation. I found them on craigslist for $7 each - with tubes. I haven't had any failures in almost 2 years.