Recently replaced a 2-foot rapid-start fluorescent fixture that is paralleled with a ceiling fan/fixture combo off of one switch. When the circuit is closed the fluorescent fixture will not start every time on it's own. However, (when it doesn't start) if I shuffle my feet to build up static electricity and simply wave my hand in front of the fluorescent lamp it will start right up. What is happening here? I noticed that there appears to be some type of flexible cable run from the fan to the fluorescent fixture that is powering the equipment with 18 AWG size wires. Couldn't tell what type because of the numerous coats of paint that it has gotten over the years (the cable was exposed on the inside of the cabinet leading to the fixture). All the splices are good. Is it simply a matter of the small wire size feeding the fixture not allowing enough initial power to start the lamp? I already recommended replacing the flexible cable with proper cabling, but the homeowner wants to wait until the kitchen is remodeled in a couple of months.
fluorescent fixtures
- Thread starter jemsvcs
- Start date
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Re: fluorescent fixtures
Aside from the issue of whether or not the cable is up to code. Does the cable contain a ground wire? I have heard of problems with florescent fixtures not operating properly when they are not grounded.
Opps, Tonyi types a little faster than I do.
[ December 21, 2003, 08:46 PM: Message edited by: crash ]
Aside from the issue of whether or not the cable is up to code. Does the cable contain a ground wire? I have heard of problems with florescent fixtures not operating properly when they are not grounded.
Opps, Tonyi types a little faster than I do.
[ December 21, 2003, 08:46 PM: Message edited by: crash ]
speedypetey
Senior Member
- Location
- Hudson Valley, NY
Re: fluorescent fixtures
I'll add my vote for bad ground.
I'll add my vote for bad ground.
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
Re: fluorescent fixtures
Florescent lights require the bulbs to be mounted within 1/2" of a grounded reflector. the capacitance between the bulb and grounded reflector causes the electrons to flow down the tub more efficiently. The are some two wire fixtures that use a higher voltage or a cap in the ballast to get the same results but many older fixtures needed the ground. try connection a ground wire to it. it will probably light on its own.
But I have seen where someone would cheat and use the neutral but this is not safe as if the neutral ever opens to the fixture it will leave lethal voltages on the fixture case.
[ December 21, 2003, 10:30 PM: Message edited by: hurk27 ]
Florescent lights require the bulbs to be mounted within 1/2" of a grounded reflector. the capacitance between the bulb and grounded reflector causes the electrons to flow down the tub more efficiently. The are some two wire fixtures that use a higher voltage or a cap in the ballast to get the same results but many older fixtures needed the ground. try connection a ground wire to it. it will probably light on its own.
But I have seen where someone would cheat and use the neutral but this is not safe as if the neutral ever opens to the fixture it will leave lethal voltages on the fixture case.
[ December 21, 2003, 10:30 PM: Message edited by: hurk27 ]
alan mcneil
Member
- Location
- Massachusetts
Re: fluorescent fixtures
yup, no ground, run your finger along the length of the tube and it will probably light.
yup, no ground, run your finger along the length of the tube and it will probably light.
hbiss
EC, Westchester, New York NEC: 2014
- Location
- Hawthorne, New York NEC: 2014
- Occupation
- EC
Re: fluorescent fixtures
Have you got the correct lamps installed as listed on the ballast? Grounded or not I've seen fixtures do this and I refuse to believe a fixture has to have a ground to operate.
Have you got the correct lamps installed as listed on the ballast? Grounded or not I've seen fixtures do this and I refuse to believe a fixture has to have a ground to operate.
- Location
- Massachusetts
hbiss
EC, Westchester, New York NEC: 2014
- Location
- Hawthorne, New York NEC: 2014
- Occupation
- EC
Re: fluorescent fixtures
Iwire, your quote is only somebodies opinion.
I think that the confusion is caused by the ballast manufacturers literature that indeed says that the fixture must be grounded for the lamps to light or light reliably. What you need to understand is that by "grounded" they are saying that the sheet metal fixture must be electrically connected or "grounded" to the metal ballast case. Further, this "grounded" sheetmetal must be within 1/2 inch of the lamps. THAT makes sense, especially if you consider that the circuitry within the ballast could have a connection to the case for this purpose.
I have not seen a plausable explanation yet for why connecting the fixture to an equipment grounding conductor that just goes back to the neutral would have anything to do with the lamps not lighting.
Anytime I've seen a problem like this it has been caused by a bad ballast, improper wiring within the fixture, bad lamps or improper lamps. The latter is very easy to do these days and is probably the most common reason for a new fixture not working.
Iwire, your quote is only somebodies opinion.
I think that the confusion is caused by the ballast manufacturers literature that indeed says that the fixture must be grounded for the lamps to light or light reliably. What you need to understand is that by "grounded" they are saying that the sheet metal fixture must be electrically connected or "grounded" to the metal ballast case. Further, this "grounded" sheetmetal must be within 1/2 inch of the lamps. THAT makes sense, especially if you consider that the circuitry within the ballast could have a connection to the case for this purpose.
I have not seen a plausable explanation yet for why connecting the fixture to an equipment grounding conductor that just goes back to the neutral would have anything to do with the lamps not lighting.
Anytime I've seen a problem like this it has been caused by a bad ballast, improper wiring within the fixture, bad lamps or improper lamps. The latter is very easy to do these days and is probably the most common reason for a new fixture not working.
tonyi
Senior Member
Re: fluorescent fixtures
Is this capacitive linkage large enough to induce 4-5ma leakage to gnd? (I've seen correctly wired and grounded flourescents trip GFCI's and this would be a plausable explanation for that behavior)
[ December 22, 2003, 07:46 PM: Message edited by: tonyi ]
Is this capacitive linkage large enough to induce 4-5ma leakage to gnd? (I've seen correctly wired and grounded flourescents trip GFCI's and this would be a plausable explanation for that behavior)
[ December 22, 2003, 07:46 PM: Message edited by: tonyi ]
A
a.wayne3@verizon.net
Guest
Re: fluorescent fixtures
We have one builder that supplies their own fixtures,Thomas brand.We were getting these 2 ft.flourescents for closets,that simply didn`t work,1 out of 3 would not start completly.A rep from Thomas met myself and the project manager.He said that the E.E. from their company stated that the ballasts had to be used for 100 hours before thay would work correctly
In a home that only occasionally uses these fixtures that could take mmmmmm months.I simply replaced the ballasts supplied with advance replacement ballasts and problem solved.The worst part was since they supplied all their own fixtures they paid service calls to fix them.$$$$$$$ became an issue and now we supply the fixtures
We have one builder that supplies their own fixtures,Thomas brand.We were getting these 2 ft.flourescents for closets,that simply didn`t work,1 out of 3 would not start completly.A rep from Thomas met myself and the project manager.He said that the E.E. from their company stated that the ballasts had to be used for 100 hours before thay would work correctly
In a home that only occasionally uses these fixtures that could take mmmmmm months.I simply replaced the ballasts supplied with advance replacement ballasts and problem solved.The worst part was since they supplied all their own fixtures they paid service calls to fix them.$$$$$$$ became an issue and now we supply the fixtures
- Location
- Massachusetts
Re: fluorescent fixtures
OK can you explain why the lamps start if you touch them?
goldstar
Senior Member
- Location
- New Jersey
- Occupation
- Electrical Contractor
Re: fluorescent fixtures
I'm on the side with those in favor of properly grounding the fixture. I can tell you from a recent experience that this is the case. I was called by a friend to check some shoddy workmanship to their recent addition. One of their problems was that their closet fluorescent fixtures would not start for several minutes. ( These were small, under-cabinet type fixtures). When I stood on a ladder and touched the fixture it illuminated. I shut the switch and tried again - same thing - it would not start until I touched the fixture. I originally thought it might have been the bulb so I replaced it and had the same experience. It wasn't until I removed the fixture from the ceiling that I realized that the electrician (I use that term loosely) before me installed a 4" round box in the ceiling, curled up the EGC and stuffed it in the box, ran the remaining black and white conductors thru a metal romex connector and spliced it to the ballast wires. Once I properly spliced on a piece of NMC and properly grounded the fixture it worked perfectly.
Believe what you want but "seeing is believing" for me. Besides.....isn't the fixture SUPPOSED to be grounded in the first place ?
I'm on the side with those in favor of properly grounding the fixture. I can tell you from a recent experience that this is the case. I was called by a friend to check some shoddy workmanship to their recent addition. One of their problems was that their closet fluorescent fixtures would not start for several minutes. ( These were small, under-cabinet type fixtures). When I stood on a ladder and touched the fixture it illuminated. I shut the switch and tried again - same thing - it would not start until I touched the fixture. I originally thought it might have been the bulb so I replaced it and had the same experience. It wasn't until I removed the fixture from the ceiling that I realized that the electrician (I use that term loosely) before me installed a 4" round box in the ceiling, curled up the EGC and stuffed it in the box, ran the remaining black and white conductors thru a metal romex connector and spliced it to the ballast wires. Once I properly spliced on a piece of NMC and properly grounded the fixture it worked perfectly.
Believe what you want but "seeing is believing" for me. Besides.....isn't the fixture SUPPOSED to be grounded in the first place ?
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