I am posting this to the woodworking group because wood workers know a lot about everything. ;-)
I am a volunteer at church and one of things that I do is change the florescent lights when they die. Most of the fixtures are four tube fixtures.
Is there a test to tell if a Florescent light tube is bad and needs to be replaced, or the light is not working because its companion is dead?
I have struggled with this. Sometimes when one of the tubes is replaced the other seems to start working. So it would be nice to test the tube to see if even though working it should be replaced.
In the hospital where I used to work, if a bulb in a fixture went out they replaced all 4 bulbs. Since they always did that, when one went out all the others were the same age and likely to go before long. Apparently this practice was cost effective for them. But then, their maintenance crew was being paid.
I always replace just the bad one. In fact, did that today.
In the hospital where I used to work, if a bulb in a fixture went out they replaced all 4 bulbs. Since they always did that, when one went out all the others were the same age and likely to go before long. Apparently this practice was cost effective for them. But then, their maintenance crew was being paid.
I always replace just the bad one. In fact, did that today.
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I have a bunch of 8' cans hanging from chains in my shop. They hold two tubes. When I notice one acting flakey I just replace both of them. Some of my 8 footers are 10 years old, and I have yet to replace a ballast. All of the cans are ten years old.
When I was a kid one of my chores was replacing the tubes in the 4' cans above the drop ceiling in our family grocery store. I also had to replace a number of ballasts over the years. One day I asked my dad if he thought the bulbs being bad were affecting the ballasts. He made a couple phone calls and said lets try just replacing all the bulbs on a can the instant one starts acting up and see. I replaced one or two ballasts over the next year, and then not another one until the day I left home.
I don't know how many ballasts my dad replaced after I left home, but...
A few years ago my dad stated with authority that if a tube starts acting you should just replace all the tubes on the can as your ballasts will last longer if you do. I'm not sure if he remembers our conversation from over
35 years ago, but I do.
I've never heard or read an "authority" state that to be the case, but I pretty much believe it. Given what a ballast costs I think its cheaper to just replace all the tubes the instant one tube starts to flicker or act flakey. For somebody who might need to hire an electrician the cost of a bad ballast is much more.
Almost always they begin to darken on the end/ends.
I have found that this can often be simply the connection. Wiggle the light and it comes back on. There is very little contact area on the terminals. If the connection is not good the spot can corrode.
I was once told be a lighting salesman that the failing tubes can cause a ballast to go bad. Cheaper to replace all tubes, maybe. I have 4 tube fixtures and the ballasts cost $12. If the lamps poops out shortly after turning dark it is probably less expensive to replace the tubes at first sign, but I have seen dark ends on some tubes for months with nothing really going wrong.
It has been proven by a few studies in plant and office operations that all bulbs should be replaced at the same time. They have a different situation in that they have a paid maintenance crew but the economics of time and getting equipment to the site you do it all. Some manufacturing companies will do an entire section of a building once a certain amount of lamps are out. Of course, they are using lifts to get to 20' or higher ceilings.
I don't worry about testing. I replace them all at the same time.
Being in a church I'm going to make an assumption that the lamps are T-12. That means they are the 1" wide lamps which are becoming obsolete and/or expensive to purchase. If they are the T-12 and you will replace with the same, then change both lamps instead of one. I say both lamps since usually they have two ballast per 4 lamp fixture but if it's one ballast, then change them all.
Today's universal T-8 ballasts are much more efficient and when one lamp fails, the others will still function. Then you can just replace the failed lamp. When one T-12 lamp fails, the others on the same ballast will stop functioning but resume when the failed lamp is replaced.
The key point is location of fixtures and type of lamps. T-8 lamps don't require all to be replaced if one fails. Though, if location is high which requires anything beyond an 8 foot ladder, then yes, it is recommended to replace all.
In high bay areas, we often do a complete relamping when the % of lamp failure is 20 or more of the total quantity. This partakes several years apart. But now going to LEDs, we're hoping that problem partakes much longer with a total LED relamping.
Replacing all tubes, if it's at all difficult to reach the fixture, is certainly a good idea (won't save much money trying to get the last ten percent of life out of a tube that's turning dark). The 'cause a ballast to go bad' is probably obsolete, the old iron ballasts would sometimes overheat when a tube went out.
The reason, is that the tube going out could result in accidental rectification of the current (and magnetize/saturate/overheat the ballast).
BELL LAB PROVES EXISTENCE OF DARK SUCKERS! For years it has been believed that electric bulbs emitted light. However, recent information from Bell Labs has proven otherwise. Electric bulbs don't emit light; they suck dark. Thus they now call these bulbs dark suckers. The dark sucker theory, according to a spokesman from the Labs, proves the existence of dark, that dark has mass heavier than that of light, and that dark is faster than light.
The basis of the dark sucker theory is that electric bulbs suck dark. Take for example the dark suckers in the room where you are. There is less dark right next to them than there is elsewhere. The larger the dark sucker, the greater its capacity to suck dark. Dark suckers in a parking lot have a much greater capacity than the ones in this room.
As with all things, dark suckers don't last forever. Once they are full of dark, they can no longer suck. This is proven by the black spot on a full dark sucker. A new candle has a white wick. You will notice that after the first use, the wick turns black, representing all the dark which has been sucked into it. If you hold a pencil next to the wick of an operating candle, the tip will turn black because it got in the path of the dark flowing into the candle. Unfortunately, these primitive dark suckers have a very limited range.
There are also portable dark suckers. The bulbs in these can't handle all of the dark by themselves, and must be aided by a dark storage unit. When the dark storage unit is full, it must be either emptied or replaced before the portable dark sucker can operate again.
Dark has mass. When dark goes into a dark sucker, friction from this mass generates heat. Thus it is not wise to touch an operating dark sucker. Candles present a special problem, as the dark must travel in the solid wick instead of through glass. This generates a great amount of heat. Thus it can be very dangerous to touch an operating candle.
Dark is also heavier than light. If you swim deeper and deeper, you notice it gets darker and darker. When you reach a depth of approximately fifty feet, you are in total darkness. This is because the heavier dark sinks to the bottom of the lake and the ligher light floats to the top.
The immense power of dark can be utilized to a man's advantage. We can collect the dark that has settled to the bottom of lakes and push it through turbines, which generates electricity and helps push it to the ocean where it may be safely stored. Prior to turbines, it was much more difficult to get dark from rivers and lakes to the ocean. The Indians recognized this problem and tried to solve it. When on a river in a canoe traveling in the same direction as the flow of dark, they paddled slowly, so as not to stop the flow of dark, but when they traveled against the flow of dark, they paddled quickly so as to help push the dark along its way.
Finally, we must prove that dark is faster than light. If you stand in an illuminated room in front of a closed, dark closet, then slowly open the door, you would see the light slowly enter the closet, but since the dark is so fast, you would not be able to see the dark leave the closet.
In conclusion, Bell Labs stated that dark suckers make all our lives much easier. So the next time you look at an electric light bulb, remember that it is indeed a dark sucker.
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