# Replacing Ballast



## rjgorman (Feb 13, 2010)

I am trying to replace ballast for kitchen fixture, 4 bulb, T-8. The replacement ballast is the same on the hot side, but the feed side has 4 wires, 2 red, 2 blue. The original ballast has 8 wires, 2 red, 2 blue, 2 gray, 2 brown. How do I cut and splice the new ballast in? Thanks


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## kbsparky (Sep 11, 2008)

Any yellow wires there on the old one or the new one?

How is the old one connected?


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## SD515 (Aug 17, 2008)

May not be any yellows, kb. I think the new T8 instant starts don’t have yellow ??

OP…follow what the diagram on the new ballast shows. Don’t be concerned with the actual colors of the lampholder wires (tombstones) Just be sure the proper wire from the ballast goes to the proper tombstone, per the diagram. You’ll be connecting one wire of the ballast to 2 wires going to the (same) tombstone.

I converted a bunch of these a couple months ago where the fixture wires were different than the standard blue, red, yellow.


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## rjgorman (Feb 13, 2010)

*replacing ballast*

Yes, the one side of the new ballast is the same as the new one, 1 each black, yellow and white. It's the other side of the ballast that confuses me. The old one has 8 wires, 2 each of red, blue, gray, & brown. Each set of those goes to a different pin connector. The new ballast has only 2 blue and 2 red wires. So my problem is.. 8 wires (4 different colors) from the old and only 4 wires (2 different colors) on the new ballast.


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## rjgorman (Feb 13, 2010)

SD515 said:


> May not be any yellows, kb. I think the new T8 instant starts don’t have yellow ??
> 
> OP…follow what the diagram on the new ballast shows. Don’t be concerned with the actual colors of the lampholder wires (tombstones) Just be sure the proper wire from the ballast goes to the proper tombstone, per the diagram. You’ll be connecting one wire of the ballast to 2 wires going to the (same) tombstone.
> 
> I converted a bunch of these a couple months ago where the fixture wires were different than the standard blue, red, yellow.



OK, I think that makes sense to me now, eg, the 2 brown wires to one of the either red or blue wires... as per the wiring diagram as to which wire goes to which tombstone.


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## Missouri Bound (Apr 9, 2011)

Check the voltage on the new ballast.....And check what bulbs it is for. Seems like you may have the wrong ballast.


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## SD515 (Aug 17, 2008)

The key is to do what the diagram of the new ballast shows.

Your original ballast has 8 wires, 2 red, 2 blue, 2 gray, 2 brown. You can look at the original ballast diagram and it’ll show which does what. Compare that to what the new ballast needs.

Here’s a shot in the dark since I can’t see what you are working with, so this is only an example…..

Let’s say your original wires….the 2 reds and the 2 blues go to one end of the fixture, the browns and grays go to the other end.
I’d guess the new ballast…1 red to 1 old red, other new red to other old red, 1 new blue to old blue, other new blue to other old blue, new yellow to both old brown and to both old gray.
Only one new yellow right? 

This may or may not be correct, but it’s intended to give you an idea.


Missouri has a good point. Make sure the new ballast is correct for the voltage and type of lamps. If it is, it’ll work. You just have to get the new ballast and fixture to play together.


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## frenchelectrican (Apr 12, 2006)

If my hunch is correct the old one was rapid start therefore there is a reason why extra wire show up.

Do the new ballast say 4 lamp or 2 lamp ?? that is important part due some of the electronic instat start ballast will wired complety diffrent than rapid start ballast.

If you are converting from rapid start to instat start there is one more step you will have to do is shunt the tombstone or tie two wires together { this is the only way you can have good life on the bulbs itself if not it will shorten the life a bit }

And what colour ballast label genrally black or white label is typically used with 120 volts circuit the red or orange is typically used on 277 volts unless your ballast say multi voltage so it will work one of few voltage without issue.

Also the last thing is make sure you ground them good otherwise you will have hard time to get it lit up.

Merci,
Marc


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## rjgorman (Feb 13, 2010)

Missouri Bound said:


> Check the voltage on the new ballast.....And check what bulbs it is for. Seems like you may have the wrong ballast.


No, its the correct ballast, 120 V, 4 bulbs, T-8


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## rjgorman (Feb 13, 2010)

SD515 said:


> The key is to do what the diagram of the new ballast shows.
> 
> Your original ballast has 8 wires, 2 red, 2 blue, 2 gray, 2 brown. You can look at the original ballast diagram and it’ll show which does what. Compare that to what the new ballast needs.
> 
> ...


Thanks, and I am getting some insight. I am sure the ballast is correct, 120v, 4 bulbs, T-8. Now, in response you what you say, no.. all 8 of the wires in question go to the same end of the fixture...eg both brown go to one tombstone, both gray to another, and so forth. At the other end all the tombstones are series connected with common yellow wire. I am getting the impression that this is a 'new' type ballast. From what some have said here, I think perhaps what I need to do is look at the wiring diagram for the new ballast, see what wires are meant for what tombstone and then combine the two corresponding wires from the old ballast and splice them into one of the leads of the new... for example... both brown wires from old to one of the red wires of the new. This is the best I can figure out.


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## SD515 (Aug 17, 2008)

rjgorman said:


> ... From what some have said here, I think perhaps what I need to do is look at the wiring diagram for the new ballast, see what wires are meant for what tombstone and then combine the two corresponding wires from the old ballast and splice them into one of the leads of the new... for example... both brown wires from old to one of the red wires of the new. This is the best I can figure out.


Yep, compare the 2 diagrams...you're on the right track. Be aware you may have to add or remove jumpers at the tombstones themselves, but there's a good chance you won't have to.

If there's a common yellow at one end of the fixture, it'll probably go to the new yellow, and one of the new wires to a pair of the old. Again, check diagrams.


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