I have an old house (1865) and it has knob & tube wiring. I have a fluorescent kitchen light with an older flip switch which goes up or down. It is a three way, with a switch on each side of the kitchen, and I have to flip the switch several times for it to come on. My question is can this be dangeruos or just inconvienient? Thanks in advance

The fluorescent fixture is not working properly because the wiring does not have a equipment grounding conductor, and one is needed for any fluorescent fixture to start.

You may notice that the fixture seems to work OK on humid days or those with high relative humidity, and will not work on days that are dry.

All receptacles, light fixtures, and switches now and for some time are required to be grounded. Your fixture is not necessarily unsafe to operate as it is out of reach, but the lack of grounding is needed to operate properly.

Any chance of changing the fixture to an incandescent fixture?

Not sure if we can change the fixture right now.. can I change the switch and ground the fixture or do I need something else?

You said older flip switch, how old? How old is the fluorescent light fixture? Does it have "starter" (looks sort of like a small "C" size battery)? Does the same thing happen at both switches. If you turn the switch on and wait a while does the light eventually come on? Has it always done this of is this something new?

Uhh, TKRussell, he didn't say the light wasn't working correctly, he said the switch wouldn't turn the light on immediately. My first guess is that the switch is shot. I have some experience with 'no ground' wiring and know that fluorescent lights were around long before the grounding conductor came into general use. And tired switches are common.

The most common reason a FL doesn't work correctly is end of lamp life. 2nd is dirty tubes and fixtures, although usually when that becomes a problem, end of life is not far off. 3rd reason is a bad ballast. Somewhere down the list farther is ungrounded fixture.

Interesting note here. I have a 4' 2 tube fixture in a kitchen that has knob & tube wiring. The magnetic ballast cooked out and the fixture had to be replaced. I called a well known ballast manufacturer and asked an engineer what would be recommended for this situation, would an electronic ballast work w/o a ground or should I use a rapid start magnetic ballast fixture like the original? He immediately said I should install a ground. I said I am not ripping the plaster ceiling, fiberglas insulation, walls and doors out at this point in time just to run a ground. When he got it through his head that there was NO possibility of installing a ground, he said that an electronic ballast was the best choice in this situation. The light has been running for several years of daily use now and I have had no complaints. Now if you are starting the lamps in cold temperatures it makes much more of a difference.

EPMiller

Uhh,EP, there are at least two switches, so the poster should be able to determine if the problem is a switch. Sure a switch can be changed as part of troubleshooting, however I am offering a popular reason for a problem with wiring that has no ground.

Fluorescent fixtures require grounding to start. Don't discount my advice without reviewing available backup:

Shown in this troubleshooting list:
American Fluorescent (http://www.americanfluorescent.com/display/technical/troubleshooting.php)

And by Item 5 from Advance Ballast:

http://www.advance.philips.com/documents/uploads/literature/443529026841.pdf

Includes electronic.

They may work, then some days they may not. You have been lucky.

Do more web search for many other sites that back up my advice.

Mt, try an electronic ballast, keeping in mind, at least one manufacturer states grounding is needed. I have no other advice except install a grounded circuit to the fixture.

Uhh,EP, there are at least two switches, so the poster should be able to determine if the problem is a switch. Sure a switch can be changed as part of troubleshooting, however I am offering a popular reason for a problem with wiring that has no ground.
Agreed, but I still stand by what I said. If nothing has been changed lately on the circuit and the light just recently started acting up my checks are 1) end of lamp life, 2) dirty tubes and fixture, 3) ballast, 4) power supply, 5) other things. Agreed that I jumped right to #4, but I assumed that the poster would have checked the tubes already. The age of the wiring brought a bad switch to mind. Also the use of the singular in describing what he does when turning the light on, made me think it was one of the switches. Probably bad assumption in hindsight. If it is just grounding, the problem should have been there all along.

Fluorescent fixtures require grounding to start. Don't discount my advice without reviewing available backup: <snip web resources> Includes electronic.
Yes, I distributed a copy of one of those, from Advance I believe, to my coworkers several years ago. I am familiar with correct procedure.

They may work, then some days they may not. You have been lucky <snip>
How can the original fixture in my kitchen have been just "lucky" for 40 years or so? Agreed that they will not start as easily w/o grounding, but temperature and humidity are definitely factors here.

Mt, try an electronic ballast, keeping in mind, at least one manufacturer states grounding is needed. I have no other advice except install a grounded circuit to the fixture.
Completely agree here. If at all possible, get a ground to that fixture. See the last paragraph of my previous post.

No hard feelings here, just trying to explain myself.

EPM