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#692268 - 11/09/11 02:19 PM new lights...new ballast...not working
terrapin05 Offline

Registered: 07/15/04
Posts: 198
Loc: Southern Maryland
We're talking old 8-foot flourescent fixture. Took old ballast to supply store and got the newer, smaller replacement ballast. Wired in new ballast, put in bulbs and fixture worked for about 2 hours, then noticed it was not lit. Only thing I wasn't sure is new ballast had 2 blue wires and old one only 1. I just put both blues to the blue in the fixture. TIA. Also, not a supply issue because it runs parallel to light in front of it and that one works.

Edited by terrapin05 (11/09/11 02:19 PM)

#692278 - 11/09/11 03:03 PM Re: new lights...new ballast...not working [Re: terrapin05]
jdevlin Offline
Carpal Tunnel

Registered: 09/09/02
Posts: 9715
Loc: Welland Ont. Canada
You need to check the wiring drawing on the ballast. I can guarantee that it doesn't have the two blue wires from the ballast connected to each other.
I suspect the new ballst is probably no good now.

Edited by jdevlin (11/09/11 03:04 PM)

#692297 - 11/09/11 04:43 PM Re: new lights...new ballast...not working [Re: terrapin05]
MCA Offline
Carpal Tunnel

Registered: 03/09/06
Posts: 4943
Loc: Illinois
As said check the diagram on the ballast. The new one is probably electronic and electronic ballasts for instant start 8 foots have an extra wire compared to the magnetic instant start 8 foots. The wiring configuration will be different. Re-wire it correctly, if it doesn't work try the tubes from a working fixture (if it works then the tubes are damaged). If it still doesn't work then the ballast may be damaged from mis-wiring.
Sometimes there is an extra lead to be capped off if it can be used for a 3rd tube. But for 8 foot fixture it is probably the different configuration for modern electronic ballasts.
Be sure you have the right tubes for the ballast (the right T and the right wattage as specified on the ballast). T8's and T12's will both fit but are not interchangible.

Edited by MCA (11/09/11 04:49 PM)

#692337 - 11/10/11 12:05 AM Re: new lights...new ballast...not working [Re: terrapin05]
MCA Offline
Carpal Tunnel

Registered: 03/09/06
Posts: 4943
Loc: Illinois

Here's a link to a diagram for an electronic 2 tube F96T12 ballast which has a black, a white, 2 blues, and a red. Even though its still a T12 it is different than an old T12 magnetic ballast that has a black, white, red, and blue.
Most likely it wires like this...
*One new ballast blue to fixture blue.
*Other new ballast blue to fixture red.
*New ballast red to both sockets at the other end of the fixture.
*New ballast white to building white.
*New ballast black to building black.

In general...
T12 rapid start (2 pin tubes) electronic ballasts wire the same way was T12 rapid start magnetic ballasts.
T12 instant start (single pin tubes) electronic ballasts wire differently than T12 instant start magnetic ballasts.
T8 modified instant start (2 pins shorted) wire differently than T12 rapid start.

Always check the ballast wiring diagram printed on the ballast.

Edited by MCA (11/10/11 12:07 AM)


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