here's a good one that has me stumped, about the above. bought a brand new fixture a couple of months ago,the rapid start type belive it's 20 watt ,two bulb. the problem is sometimes it comes on by itself sometimes not.i have changed ballasts, grounded it properly,& it still takes a notion not to work it doesn't.both ends of each bulb glow but want seem to start.but as soon as i touch the fixture it comes on.the bulbs are as close to the frame as possible.i had those $8 shoplights to work with only two wires before i got my shop wired. they never give a bit of a problem.even the ballast maker couldn't answer my problem.they even sent free replacements.but sometimes ya flip the switch & it comes right on.so i wonder what the problem coud be?

Try changing the bulbs. Since the big environmental crusade, F-lamps contain a lot less mercury than before. (The mercury vaporizes and aids in starting.)

And avoid the ones with green end caps, they're the worst!!

Even with name brands, defective bulbs seem common these days.

Agreed. I have solved this same problem by using another manufacturer's lamps. U tube fixtures are notorious for this. I have had good luck with GE bad luck with Phillips. Also, as said try to stay away from the energy saving reduced wattage low mercury ones. The full wattage energy hogs usually work best. Maybe the energy saving lamps save energy because they don't work half the time.

-Hal

Change to T8 lamps with an electronic ballast, your problem will be solved.

+1 for the T-8....


Dnk....

Just for grins & giggles, look closely at the wiring diagram on the ballast. It sometimes matters which bulb (or bulb end) gets fed first.

THANKS GUYS! i'll check on the bulbs.my parents are about to drive me nuts abot this. especially my mom!LOL!why would touching the fixture cause the to come on though?i'm lost on that one. but it seems to work every time.

when you touch the bulb you get the little molicules of phospores (sowwy spelling) excited.

Circuitman,
Do you have to wait for a while then touch the fixture for it to come on?

Could there be a loose connection or a bad/corroded connection in the line somewhere that you do not get the full supply voltage when you turn the switch on?

hi ed, no paticular time involved. was down there tonight & it came right on twice. the third time it didn't. touched it ,then it came on. sometimes you would turn it off & it would come right on.i know flourescent lamps are tempature senstive.but this doesn't seem to be the case.all connections are ok too. i may try some different bulbs.then i may attach a wire to the fixture so they can touch it.LOL!

It still sounds like a poor ground, but I also agree that certain brand combinations can be troublesome.

We had problems with Lithonia 2x2 U-tube fixtures. Philips tubes worked where Sylvania didn't (or vice versa).

I agree with Larry......poor ground. Some fluorescent fixtures will not work without a ground....especially a problem when connecting them to knob and tube wiring.

How many times have you had the customer say "I put in new tubes but it still doesn't work", only to find that the tubes just needed to be turned fully into the ends?

Flourescent lamps can sometimes be a real pain in the butt. I've had some that would only fire off when you held a piece of tin foil between the lamp and the fixture frame.
All I can say is to check that the lamps are turned to their proper position, make sure the connections at the tombstones are good, and try other lamps.
As was stated earlier, T-8s with electronic ballasts are always a good alternative.

I've started using electronic ballasts as replacements in the T12 U tube fixtures and so far so good. I'll keep my fingers crossed.

-Hal

Isn't it hard to work that way?