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tunaman 11-03-2012 07:23 PM

New T8 Light Fixture doesn't work
I had a dying T12 light fixture and since you cant buy new T12 ballasts, I just replaced it with a new 4 Bulb T8 Light Fixture.

Unfortunately this light fixture doesnt work. I hooked up my voltage meter to it and it shows 116 volts at the line going into it. Would 4 volts off cause the light not to fire? Any ideas to try and get it to work?

Edit: In a 4 bulb fixture I do only have 2 bulbs in it. Is that OK, or do I need to have all 4 in?

joed 11-03-2012 08:29 PM

Try it with all 4 lamps. The T8 fixtures we use do allow removal of lamps. I'm not sure if that is true of all of them.
Another issue could be grounding. Some fixtures require a ground to fire the tube properly.

tunaman 11-03-2012 08:40 PM

There is a green ground screw in the frame (not hooked to the ballast) but on the fixture I took out it was not hooked up so figured this one would be the same. The instructions dont even mention the ground. There was just black and white wires coming in to the original fixture. There is a ground screwed in to the junction box about 12 feet away.

Dierte 11-03-2012 10:05 PM

Put all lamps in. Some fixtures require all lamps to fire

Marc05 11-03-2012 10:25 PM

Check that it has a 120v ballast inside.

Jim Port 11-03-2012 10:34 PM

Check the wiring going to the sockets. there is a good chance it needs to be changed. A diagram will be on the ballast.

tunaman 11-04-2012 01:04 AM

I will get 2 more bulbs tomorrow. Im hoping that is the problem. Yes it says in big letters 120 vollts. I know I wired it correctly. I took one look at the wiring and it is obvious. All the prewired wiring is color coded and cut to just the right length. 2 long yellows for the ends, and a red and blue for the middle. And for the power black to black and white to white. I took this fixture out of the box new today.

Thanks guys, I knew I wired it right but I have never really done lighting before so wasnt sure if there was something I might have been missing. If adding 2 bulbs doesnt work tomorrow, im replacing the fixture.

frenchelectrican 11-04-2012 01:31 AM

What the ballast part number is on stamped on it so the reason why I can able indentify if you have rapid start or instat start ballast.

Note the rapid start they always wired in series of pairs of bulbs so you will need two bulbs to get one set lit up. The instat start verison will useally wired in either way but most case in parallel mode so any numbers of lamp will get it running.

Again post the number and we will go from there.


tunaman 11-04-2012 01:41 AM

ap rc 432ip 120 - 1 it is labeled instant start ballast.

frenchelectrican 11-04-2012 01:48 AM


Originally Posted by tunaman (Post 1044329)
ap rc 432ip 120 - 1 it is labeled instant start ballast.

Parallel connection.

Second thing is check the tombstone to make sure the connection is good some case the conductors can come loose from factory which I have see it once a while.

You will need 4 lamps to get this light up first time.

And try to switch the red et bleu socket around some case it will work.

If that fail to light up then take a test lamp or use the tempory outdoor pigtail light socket and use with 60 watt bulb and hook it up tempory to make sure you actually have good source due some of the DVM ( digial voltmeter ) don't actually put a load on espcally with a bad connection which it will show up.

If your test light don't come on then you have issue with supply you may want to check the connection and splices at the junction box ditto with switch box if the netural is there.


tunaman 11-04-2012 02:41 AM

My connections are all solid. I double checked them when it wasnt working. I have good power all the way up to the leads for the fixture. I bet 2 more bulbs will work.

tunaman 11-04-2012 11:07 AM

I went and got 2 bulbs today and nope, no go. Put in all 4 bulbs and I do not have light. Im not sure what I could have done wrong but I guess maybe fixture bad.

Oso954 11-04-2012 03:31 PM

I think you are overlooking the grounding issue. Some lamps may not start with the ground missing.

Your instructions (step 3) tell you to connect the ground. They mention the ground, before the supply wires.

Maybe you should give Lithonia a call and see if they can help you.

tunaman 11-04-2012 06:02 PM

I added a ground wire, just from the ground screw to a nearby junction box with a ground wire and no go.

Jim Port 11-04-2012 06:04 PM

Is the other junction box grounded?

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