T12 bulbs with T8 ballasts

[MrFixit1599]

For various reasons that go beyond this post, I had a bunch of T12 bulbs and T8 ballasts that were all free to me for my garage. Original setup was a T12 series system that supposedly came out of a church that the previous owner installed. A lot of the old original T12 ballasts were dead, so I replaced them with the T8 ballasts. The T12 bulbs with the T8 ballast seem dimmer than the actual T12 ballast driven T12 bulbs, which is a given considering the wattage difference. Other than a shortened lifespan for bulbs and ballasts, is this really a problem? It is just for my garage, and only gets used a few hours a week.

I know it is not technically correct, but it is hard to turn down 15 free ballasts and 50 free bulbs when half of your lights work.

Thanks for any advice.

Aaron

 

[goldstar]

I don't know the exact technical reason but suffice it to say that the technology to light a T12 bulb is far different that that of a T8. I know free often seems awfully tempting at times but as you've experienced your T12 bulbs will not come to full illumination when driven by a T8 ballast.

 

[norcal]

Never tried T12 lamps w/a T8 ballast,, but T8 lamps used w/a T12 ballast will result in premature lamp failure.

 

[mbrooke]

Ive tried T12s in a T8 ballast. The lamps fire but run a bit dimmer. T8 in a magnetic T12 is a definite no.

 

[goldstar]

Ive tried T12s in a T8 ballast. The lamps fire but run a bit dimmer. T8 in a magnetic T12 is a definite no.

Being for free I would imagine that's what he has.

 

[kwired]

... Other than a shortened lifespan for bulbs and ballasts, is this really a problem? It is just for my garage, and only gets used a few hours a week.

I know it is not technically correct, but it is hard to turn down 15 free ballasts and 50 free bulbs when half of your lights work.

Thanks for any advice.

Aaron

I don't believe you see any significant increase in the risk of burning the place down or electrocuting anyone, if that is what you are wanting to know.

Performance wise - remember what you paid for it.

 

[Fulthrotl]

I know it is not technically correct, but it is hard to turn down 15 free ballasts and 50 free bulbs when half of your lights work.

Thanks for any advice.

Aaron

how big is the garage?

three 2 tube 48" T8's from home desperate are about $100 retail.

so $100 worth of lights would probably get you all squared up....
is your house worth investing $100 in?

 

[Little Bill]

I do a lot of light repair, mostly ballast replacements and retro fit.
From what I've seen when people (unknowingly) install T12 lamps with a T8 ballast, the T8 ballast will fail within a year.

 

[junkhound]

If the T12 bulbs are 60 W, OP will not have a problem. If he came by a stash of old 90W bulbs, or tries to use HO bulbs, some mfg electronic ballasts may fail early used in high tambient temperatures, most will be ok as they are self limiting.

50 years ago when I was first starting out, lighting textbooks went into great detail on why 1.5" dia bulbs were the highest lumens per watt.

Phosphors and electronics have come a long way since then, not to mention being able to reduce Hg to 4 mg in some T8 96" bulbs.

I've used 4 ft T12 on T8 electronic ballasts ever since electronic ballasts were first available just to 'use up' existing F48T12 bulbs, never have had an electronic ballast fail. 32W F48T12, not older 40 W bulbs.

 

[Dennis Alwon]

I do a lot of light repair, mostly ballast replacements and retro fit.
From what I've seen when people (unknowingly) install T12 lamps with a T8 ballast, the T8 ballast will fail within a year.

I agree the t-8 ballast (electronic ballast) don't last long however we can't even get the old ballasts anymore so we change them to electronic.

 

[steve66]

What you won't know is how efficiently these are producing light, and how much power they are using.

Free might not be free after all since you have to pay for the power.

 

[kwired]

What you won't know is how efficiently these are producing light, and how much power they are using.

Free might not be free after all since you have to pay for the power.

True but bottom line is the investment plus the energy paid for.

A few years ago when power companies were offering rebates for converting T12 lamps to T8 I had one store with 1960's 8' T12 stem mounted luminaires - stem hung from original ceiling and passed thru an added suspended ceiling. We replaced with lay in troffers and got a nearly instant make over of the place just by doing that. Did not really figure the payback on that one - they needed to do it either way.

Other places however really depended on how much run time they got before it was worth the replacement - even with rebates from POCO. A few places we decided not to make the replacement but rather change to T8 as ballasts failed, they were going to take more then 10 years to payback in some of those cases.

 

[MrFixit1599]

OP Here

OP Here

Thanks for all the input.

The guy that had the place before was using the garage as a grow house or something. It's a 1.5 car garage with 16 assemblies. I've only done half of them and its lit up in there like a stage show in Las Vegas.

So now instead of running 16 T12 ballasts that buzzed and made all kinds of racket without actually lighting the majority of the light bulbs, I have 8 that are working nice and quietly, and just leave the other 2 rows turned off.

I have to assume that even though I am not running them right, my electric savings is going to be significant. Power to 16 T12 ballasts versus 8 T8 ballasts has to be considerably less.

 

[kwired]

Thanks for all the input.

The guy that had the place before was using the garage as a grow house or something. It's a 1.5 car garage with 16 assemblies. I've only done half of them and its lit up in there like a stage show in Las Vegas.

So now instead of running 16 T12 ballasts that buzzed and made all kinds of racket without actually lighting the majority of the light bulbs, I have 8 that are working nice and quietly, and just leave the other 2 rows turned off.

I have to assume that even though I am not running them right, my electric savings is going to be significant. Power to 16 T12 ballasts versus 8 T8 ballasts has to be considerably less.

Considerable in reference to original energy usage. Dollars spent on energy will see little impact if there is little run time to begin with. If you only used a dollar of energy a month on these lights before changes, you won't really see the impact on the energy bill if there is considerable load elsewhere, though you did still reduce consumption from what it would have been.

 

[MrFixit1599]

Garage power update

Garage power update

Ok, finally getting everything situated in the garage. Long story. Anyways, before, if I had all 16 lights on, which I kinda had to since only half of them worked, I could not run my air compressor or welder very long without tripping the breaker. Today I added a mini beer fridge, and used the welder and specifically the air compressor A LOT. Even tried to get an old tube tv running, which is another long story.

Long story short, the new ballasts must draw a significantly less amount of power than the old ones. Before I could only run 8 lights, of which only 4 worked, and use the compressor or the welder. Now I can have a fridge running, plus a TV, and the air compressor, and the welder, and also have lights. What a concept.