Fluorescent lighting issue??

[jahilliard]

At a commercial bldg with multiple tenants, I was asked about a problem with one tenants fluorescent ltg. Problem: Sometimes when they turn the switch on the lights (all of them) do not turn on at all. Sometimes they turn on immediately. Sometimes they may go all day with the lights never coming on. The unit they are in is sepreated at the office and warehouse. The warehouse portion is affected the same way. It doesn't just happen with some of the lights, they all either work or don't work in that area of their unit (office or warehouse). Sometimes the office works but the warehouse doesn't. The switches seem to be fine and I am not sure if any other tenants of the same bldg are having the same problem or not. I haven't tested voltage or looked at the service or anything at all at this point, I was asked about it and I said I would post something. We are in South Florida so cold of any kind isn't a factor but there is terrible lighting daily. Any suggestions??

 

[480sparky]

Sounds like a voltage problem. But until you get in their and start rooting around, there's not much chance you'll find a sure-fire cure.

I would suspect an open neutral on a MWBC.

 

[LarryFine]

If the problem affects every light or none, it's gotta be something other than the lights. Even with a marginal voltage, not every light would have the exact same threshold.

I would try measuring the line-to-neutral voltage at a ballast. If it's not correct, try at the switch; line side voltage with the switch off, and load side voltage with it on.

I'd start with a solenoid tester, and switch to a voltmeter if the former seemed to indicate the lights should be working. There's a supply-circuit issue somewhere.

Added: Of course, there could be an unusual problem, like crossed wires somewhere (tenant A controlling tenant B's lights) or an intermittent feeder conductor.

Added again: Maybe a photocell or time clock controlling the wrong lighting circuits? Only lights are affected, right? Never receptacles or any other equipment?

 

[Mr. Bill]

Are these lights on a 3-way switch? Check if the wiring was done wrong.

 

[ultramegabob]

Are these lights on a 3-way switch? Check if the wiring was done wrong.

I have seen this more than once, about a week ago as a matter of fact. its funny how many years someone can go using only one switch on a three way set up not realizing they have a problem, and then someone new comes along and flips the other switch and the lights no longer work

 

[lat1]

I'd start with a solenoid tester, and switch to a voltmeter if the former seemed to indicate the lights should be working. There's a supply-circuit issue somewhere.

why is a wiggy better for this applicaction?

 

[highvolts582]

start from the beggining and disconnect the feed completely and test along like that Ive had some head burners but i find start from the source and disconnect the source completely then test along.

 

[LarryFine]

why is a wiggy better for this applicaction?

Because what really matters is that you're getting a real 120v that can supply a real load, and not a phantom (induced) voltage that only a high-impedance meter will read.

A voltmeter is great when you want to know the exact voltage of a supply, especially when it's under load. For troubleshooting, you need to know whether you've got power.

 

[mcclary's electrical]

I bet they are magnetic ballast and sometimes they start,,,,sometimes they don't. Convert to solid state t8's and be done with it

 

[LarryFine]

I bet they are magnetic ballast and sometimes they start,,,,sometimes they don't. Convert to solid state t8's and be done with it

But, if it's a sometimes-they-start-sometimes-they-don't issue, the entire switched group wouldn't work or fail as a group.

This is like pinpointing an intermittent electrical issue. If it affects more than one circuit, it within, or ahead of, the panel.

The farthest downstream this problem could be would be the first point or J-box where the switched conductors split off.

 

[mcclary's electrical]

You're absolutely right. I read the first post wrong. I didn't see that ALL of them were not coming on!. I was way off. Maybe the issue is the lighting contactor. I've seen the coil in more than one swell up slightly and prohibits free movement of the contacts. If there's no contactor,,,there's probably a loose joint in one of the first lights that the leg gets to.

 

[Brian Oshman]

Also, check ground integrity if all other suggested checks are OK. Fluorescents driven with mag ballasts require a ground plane to ignite and it is possible that the ground has been compromised and affecting the whole circuit.

How old are the lamps? Could be bad lamps. In warehousing, sometimes lamps are left on for years and will stay lit fine but the cathodes deteriorate and when you turn them off and back on they will never relight or struggle to.

 

[broadgage]

Presuming that this is a relativly large installation, with lights on a number of branch circuits, then I would suspect a hidden or forgotten about contactor.

This contactor may be controlled by a photocell, or a timeswitch, or a regular wall switch in some unlikely location, perhaps in another tenancy.
Or, as others suggest, a defective contactor.

Or the supply to the contactor coil might be from some unsuitable source (possibly in another tenancy) that is not allways energised.

I very much doubt that defective grounding is the problem. Although some flourescent lamp ballasts require a ground for reliable starting, they often start without a ground, and on a large installation I would expect at least some lamps to start.

Likewise at low line voltage I would some lamps to light, even if dimly or flickering.

If on the other hand we are talking about a relativly small installation with a single branch circuit, then the most likely cause is an intermitant open circuit at the switch, or the first lamp, or in between.
Other causes might be wrong, or at least unusuall, switching with two switches in series, such that both must be on to light the lamps, or wrongly wired multi way switching.