Two bulb ballast with separate bulb wiring

[JHZR2]

I’m putting a new ballast in an old fixture, and the wiring isn’t what I’d expect. My anticipated way was to separate two-wire feeds, and then the common return where the one tombstone was in parallel with the other, just jumpered over.

instead it was two dedicated sets of conductors,mSo each bulb had its own specific set.

In the image above, the top (8-wire)is how it was set up, and the bottom (10-wire) is how the wiring came with the new ballast, and how I rewired my fixture as a result.

The rewired fixture works great. But I don’t understand why they set it up this way. I don’t think it’s really any more redundant or reliable.

Im still running f20t12 bulbs in there. They start and run fine.

Any ideas? I don’t understand lighting very well….

 

[mk378]

It has to do with how the ballast works internally. The 10-wire scheme can more readily sense and regulate the current flow through each tube.

Make sure the size/wattage designation of the installed tubes is one that is exactly listed on the ballast label.

 

[JHZR2]

It has to do with how the ballast works internally. The 10-wire scheme can more readily sense and regulate the current flow through each tube.

Make sure the size/wattage designation of the installed tubes is one that is exactly listed on the ballast label.

Yes!

Still running F40T12 because they work. I guess with this setup I can mix a T8 and T12 or even an LES in there?

 

[Gyro Gearloose]

All of the two bulb florescent fixtures that I’ve purchased since electronic ballasts came out have treated each bulb as a totally separate circuit. One bulb or even one side of the ballast can go out and the other side continues working normally.

 

[mk378]

Yes you can use two different bulbs as long as they are both on the list. T8 bulbs are usually used with an instant start ballast as that offers slightly better energy efficiency, but those ballasts do not work with T12s. If you're going to convert to LED tubes, use the type which accepts 120 volts directly at the tube, and remove the ballast.

 

[2005jettatdi]

Remove the ballast and install direct wire LED tubes. It is the only logical way to go. Also pretty simple if you can read directions.

 

[JHZR2]

Remove the ballast and install direct wire LED tubes. It is the only logical way to go. Also pretty simple if you can read directions.

I have enough fluorescent tubes that the replacement of a ballast is a far cheaper path for now.

 

[2005jettatdi]

I have enough fluorescent tubes that the replacement of a ballast is a far cheaper path for now.

I have lots of fluorescent too. LEDs don't put out the heat of the ballast, light right away, last longer and give off more light. I am sticking with my advice. You can have my brand new fluorescent tubes if you want them.

 

[y_p_w]

I have lots of fluorescent too. LEDs don't put out the heat of the ballast, light right away, last longer and give off more light. I am sticking with my advice. You can have my brand new fluorescent tubes if you want them.

Had one fail. Really weird too as it seemed that the pins had splayed and the contact with the tombstones was marginal. I didn’t really do anything to cause that, but I put in a warranty request and toggled sent a replacement within a week. I just sent in video of the bad tube and didn’t have to return it. I then took it apart. Pretty simple inside. Just a DC conversion and a row of LED strip lighting. I think they were all provided low voltage in parallel, so if one LED died it wouldn’t take out the rest.

 

[JHZR2]

I have lots of fluorescent too. LEDs don't put out the heat of the ballast, light right away, last longer and give off more light. I am sticking with my advice. You can have my brand new fluorescent tubes if you want them.

I’d gladly take them if you’re close. For most of the applications I’m replacing ballasts they’ll last another 20+ years and the cost savings from a led will never cover their cost.

I did install led bulbs in some 8’ fixtures in one of my garages and they aren’t nearly as bright as the fluorescent tubes I have in there.

Purpose made LED, like my HF 5000 lumen fixtures are quite excellent.