Any tips on how to do this? I don't want to fry my meter so I figured I'd ask first. I know 120v AC goes in the ballast but what comes out? (4' 2 bulb fixtures) Since there's 2 prongs on either end, do I test from either prong on one end to either prong on the other end of the same bulb? And what should it read if it's working right?
Thanks
I wouldn't be doing that.
There are some pretty nasty voltages used to strike the lamp, and a lot of current can flow until the ballast chokes the flow.
Just substitute another tube to check it. If you want to test the ballast, it must be disconnected from the mains before you do anything.
If in doubt, ask someone at a specialized lighting store that knows these things, or consult an electrician. For the cost of a ballast today, it's not worth destroying a meter or hurting yourself. Getting a shock is half the fun, when you're thrown back and hit something, that is the other half.
If you are talking about a fixture that's "gone bad", first replace BOTH bulbs with two others that you just saw working properly. If the fixture works, one or both of the original tubes is bad. Keep trading bulbs until you get the fixture working again, and then discard the bad bulbs.
If this doesn't work, odds are the ballast is bad. To find out if it is, the easiest thing to do is to replace the ballast. With the power disconnected, open the fixture. The ballast should have on it a piece of paper with a model number and a wiring diagram. Go to the store and get a replacement that matches. Wire it up the same way the old one was. The wires are color coded--it should be straighforward. When removing the old ballast, it's usually easiest to just cut the old wires that run to the sockets and hook up the new wires with wire nuts.
BUT, when you disconnect the ballast from the supply (usually the black and white wires) as discussed above, you might want to put a voltmeter on the black and the white supply wires. If you don't get 120V, you'll need to stop the ballast replacement and deal with that problem first. If you've got 120V, resume the above operation.
On occasion, one will discover that this still doesn't do it. Then you're going to be into checking/replacing things like bulb sockets, etc. or looking for spooky weird things. In my experience with repairing fluorescent light fixtures, one first replaces the bulbs, then the ballast, then one gets creative. By the way, one spooky weird thing is that while ungrounded fluorescents will usually light up, they theoretically aren't supposed to unless the fixture is grounded. I've had a couple of jobs where an ungrounded fluorrescent just wasn't going to light--we ended up putting in an incandescent.
Hope this helps some, Ed
Ed
Hi, please be careful when working of flourescent lights. It is smart to have the fixture so that it can easily be disconnected for working on.
From my knowledge in the USA there are the two voltages of 120 v and 277 v used for lighting - in most instances. First I would check the recommended operating voltages of the ballast. Then check to see if the ballast that you install are rated for the bulbs that they will have to run. This information of the wattage rateing is written on the ballast as well, along with the wiring diagram on how to hook up the conductors. If this all checks out then make sure you are useing the proper bulbs, ie T12 bulbs (the thicker bulbs) are installed in a fixture with a ballast that is rated to turn these bulbs on. This is an easy mistake to make because the ballast for the T8 bulb looks identical but these bulbs are thinner.
If there are still issues with ballasts burning out then it might involve surge currents or neutral issues or improper wiring methods when replaceing the ballasts.
Hope this helps.
Frank
"If you need a helping hand, you'll find one at the end of your arm."
Hmmm...I'm starting to think I have a ground problem. The fixtures themselves are hard screwed into a metal building that's grounded. I'm only using 2 wire extension cords to power them though. I guess this might explain why I'm going through bulbs and ballasts. Brand new bulbs start turning black on the ends after just a few weeks of use. I guess it's time to do some re wiring.
Thanks all.
If the ends of the tubes are turning black in a few weeks then heater curent is not getting to that end of the tube.
You have either a bad ballast, a bad connection in the wiring going to that socket, or a bad socket that is not making up to both pins on the tube.
If you had a grounding problem you could cause the lamp to start by waveing your hand along the tubes.
Dr. Frankendiesel aka Scott Running BearSpace Mouse for president!15 year veteran fire fighterCollector of Apple //e'sRunning Bear EnterprisesHistory Channel Club life member.beatus homo qui invenit sapientiam
I'm with you, Jeff... as I have recently switched over to the higher priced spread, and do the new bulbs ever make a difference. The improvement in quality of the light is unbelievable!!!
Bob
Y'know, I read the title of this post last night. I was really tired (up late playing hockey and drinking beer the night before) and the word "ballast" only triggered the "rocks between the railroad ties" association.
So I thought, "Why? Does he want his tracks to glow in the dark?"
It takes an iron man to play with a toy iron horse.
MisterBeasley wrote: Y'know, I read the title of this post last night. I was really tired (up late playing hockey and drinking beer the night before) and the word "ballast" only triggered the "rocks between the railroad ties" association.So I thought, "Why? Does he want his tracks to glow in the dark?"
The glow in the dark ballast was a neat idea.
Seriously, stay away from the ballast outputs. Most home ballast put out 300v. to the heaters. Some heavier ones like we use in the factory around here put out close to 900vac to the heaters. Be safe . buy a new fixture.
Jerry SP FOREVER http://photobucket.com/albums/f317/GAPPLEG/
Instead of fooling around trying to test or replace a ballast and destroying a meter or electrocuting yourself in the process, I think you'd be much better off just purchasing a new fixture.
Many people don't realize it, but the green ground wire and white wire are connected together at the breaker box on the ouside of your home, so if you have a fixture that requires grounding but you're connecting it to a circuit without a ground, it would be safe to ground it through the white wire, assuming that the electricians who originally built the house didn't get the wires crossed. The purpose of the green ground wire is to cover cases of miswiring or a loose connection where the white wire is connected to ground in the breaker box.
Jeffrey-I've got both types. Someone gave me some industrial ones that are meant to be hard wired with conduit. These have no provision for a ground wire inside. Just hot & nuetral. (black/white) I assume the conduit is meant to be the ground. Since I am using 2 wire extension cords, I was relying on the mounting screws to the grounded building frame for a ground. The ballasts have no ground wires coming out of them. These are the ones that keep burning out. (bulbs and ballast)
I've been replacing these with Wally world fixtures that have a 3 wire plug built in. But I am still using a 2 wire extension cord, relying on the hard mount for a ground. These are the ones turning the tubes black. I guess I should get off my butt and run some dedicated grounded circuits to them. (and I soooo wanted to play with plaster today.)
300v-900v-THAT'S what I was wondering. I knew the ballast stepped the power up but I didn't know how much and the ballast labels didn't say. Thanks!
I've got both types. Someone gave me some industrial ones that are meant to be hard wired with conduit. These have no provision for a ground wire inside. Just hot & nuetral. (black/white) I assume the conduit is meant to be the ground. Since I am using 2 wire extension cords, I was relying on the mounting screws to the grounded building frame for a ground. The ballasts have no ground wires coming out of them. These are the ones that keep burning out. (bulbs and ballast)
I've been replacing these with Wally world fixtures that have a 3 wire plug built in. But I am still using a 2 wire extension cord, relying on the hard mount for a ground. These are the ones turning the tubes black.
Check the price of the new ballast... Probably only a couple of dollars less than a whole new fixture. then you will have new ballast, new bulbs, new sockets & more time to play trains.
Fixed my daughter's shop lights, replaced the bulbs & ballast, the ballast & bulbs were both bad also had to clean corrosion from the contacts. Would have saved money & time by replacing the fixture. Jerry
cacole wrote: it would be safe to ground it through the white wire
it would be safe to ground it through the white wire
It is a big-time violation of the Electrical code to ground "through the white wire" (except for certain dryer and range outlets). Please don't do this.
7j43k wrote: cacole wrote: it would be safe to ground it through the white wire It is a big-time violation of the Electrical code to ground "through the white wire" (except for certain dryer and range outlets). Please don't do this. Ed
The ground is there for your protection.
It is there so that should the neutral become energized, you will not have the metal parts of the fixture also energized. All it takes is some crossed wires, or in the case of a unit that plugs in with a two prong plug, the hot and neutral prongs being reversed.
That's why the power circuit is isolated from the chassis. The ground line is there to keep the chassis at ground potential, and blow the fuse should the hot or neutral line short to ground.
You should have 120V to ground, or neutral, from the hot wire. You should never have 120V from neutral to ground. If you do, there is something wrong. Like a broken wire/connection, or reversed wires.
jeffrey-wimberly wrote: 7j43k wrote: cacole wrote: it would be safe to ground it through the white wire It is a big-time violation of the Electrical code to ground "through the white wire" (except for certain dryer and range outlets). Please don't do this. EdI don't see why. In nearly every fuse/breaker box I've seen (and I've seen a lot) the white wire (neutral) and green wire (ground) are on the same connection which is bolted directly to the metal case of the box. A large bare wire, connected to the other end of this bolt goes away from the box to a grounding rod.
The electrical code requires that the neutral and the ground be bonded together at the service entrance (Section 250.28). This is typically done at the main disconnect. This is the ONLY place that there should be an electrical connection between the two--nowhere else (with the arguable possible exception of certain range and dryer circuits).
As to the "whys", I won't get into that.