Fluorescent Ceiling Fixture Problem

I have a 4 light 24" T8 fluorescent ceiling fixture that has gone completely dark. I have replaced the ballast with a new correct ballast (GE Pro 432-120RESDIY8, Product Code 93885) and have also replaced all the fluorescent bulbs (F17T8 - 24", T8, 6500K). The power is hot to the fixture. The new ballast was very carefully connected to the existing fixture wires (black/black, white/white, yellow/yellow, red/red, blue/blue) using new appropriately sized wire nuts (yellow). Notwithstanding the foregoing, the light fixture still does not light up.

Am completely at a loss why fixture is not working. All replies much appreciated.

SKBrown

 

If you used a non contact tester
you could be getting a false positive.It must be connected according to the diagram on the new ballast not how the old one was connected. If the old ballast was magnetic and the new one was electronic the connections are very different. There is no standard color code. You must connect according to the diagram on the new ballast.

 

The electrical tester is a two probe 100-300V GB HI VIS Voltage Tester that requires the probes to touch the bare wires.

The old ballast states that it is an "Instant Start Electronic Ballast" and the new ballast states that it is a "Residential Electronic Ballast".

While I am not by any stretch a knowledgeable reader of wiring schematics, comparing the two wiring diagrams seem to show that they are very similar. I.e. both wiring diagrams show the yellow wires connecting to one end of the fixture's bulb sockets and the red & blue wires show connecting to the other end of the fixture's bulb sockets. The only discernible difference between the two ballasts is that the yellow wires on the new ballast come out of the same end of the ballast as do the red & blue wires whereas the yellow wires on the old ballast came out of the other end of the ballast.

 

Did you turn on the power back on.

From that ballast you have 2 reds, 2 blues, and 2 yellows. Your light may have 2 wires coming from each socket. If so, both wires from a socket needs to be to one wire coming from the ballast.

 

Yes, power was turned off while the new ballast was installed and then turned on and off several times but light fixture still did not come on,

Each socket has just one wire connecting to the ballast; two yellow wires (two sockets each) connecting the four sockets on one end of the fixture and two red, two blue each connecting to similar wires from the ballast on the other end of the fixture.

 

Make sure all the tubes are properly seated in the sockets.

 

Yes, have "wriggled" each tube carefully to make sure they are properly seated in the sockets.

 

Sounds like you have unshunted sockets. Instant start ballasts require shunted sockets (One wire to each holder) You can manually shunt the sockets with a piece of 18AWG Solid wire.
Each socket should have four holes for the wires there should be two wires in one side (One from the ballast and one going to the other contact on the lampholder or socket) Without a shunted lampholder the fixture will not light up

 

The answer is none of the above!!

Had to get a Craigslist electrician to check out the problem ($35) Turns out that the new ballast was an out-of-the-box failure from Home Depot!!! Got replacement, installed it and works great. My very minimal electrical skills just didn't rise to the level to be able to check the continuity of the ballast.

In any event, thanks to all for your responses!

Best,

SKB

 

We should have thought of that.

 

I did think of that, but I was not home all day. In all my time as an electrician I have never had a ballast that was bad from the manufacture. Glad you got it figured out!