Universal T12 and T8 electronic ballast?

[brycenesbitt]

As I'm sure you know production of T12 lamps was phased out as of July 2012. I'm working with a building that has dozens of old magnetic T12 ballasts, and we'd like to upgrade to eliminate PCB's and save energy (50% supposedly).

And I know that the general recommendation is to upgrade ballasts to something supporting T8
.
However: my question is does anyone make an electronic ballast that either autodetects T12 vs. T8 bulbs, or at least has a switch. So rather than throwing away all the T12 bulbs (and their attendant mercury), we can switch to T8's as the T12's burn out.

 

[John120/240]

I do not know of any universal T-8 / T-12 ballast. You will still have the disposal quandry

today or 5 years from now. I say replace all of the T-12's now. The disposal cost is only going

to go up as time goes by.

 

[brycenesbitt]

I do not know of any universal T-8 / T-12 ballast. You will still have the disposal quandry
today or 5 years from now. I say replace all of the T-12's now. The disposal cost is only going to go up as time goes by.

Hold on, does that make sense? T12 and T8's cost exactly the same to dispose of here (even though the T8's have less mercury). If I trash 500 perfectly good T12's then that's an extra cost. If I let them burn out first, I maximize their value as bulbs, then pay the disposal cost anyway.

 

[John120/240]

T-12 vs T-8 effiecency comes in to play. T-8 are more effiecent. How much so I do not know.

How old are these T-12 fixtures ? You need somebody to put pencil to paper & figure all

of the angles. Inital cost, effiecency, disposal, labor etc.

 

[Electric-Light]

Short answer... you're not supposed to do it.

Long answer... T8s on T12 mag. will act up or won't start. on T12 electronic(uncommon), lamps/ballast will over-wattage and over heat.

T12s are designed for 0.43A while T8s are 0.27A. T12s will light just fine on T8 electronic as most are rated for F17 to F32 and F40T12 appears as somewhere in between those values to a T8 ballast.

Lamps will however run substantially dim as they're going to be driven around ~0.27A and they're not meant to be instant started, so life is reduced too.

Power consumption wise T12 mag > T8 > T12 on T8 ballast(however dramatic reduction in light too).

 

[brycenesbitt]

But if...

But if...

If someone made a dual mode T8 T12 ballast (with a switch), then a smooth transition would be possible, with no disposal of good bulbs. Did anyone every make such a device?

 

[Electric-Light]

Hold on, does that make sense? T12 and T8's cost exactly the same to dispose of here (even though the T8's have less mercury). If I trash 500 perfectly good T12's then that's an extra cost. If I let them burn out first, I maximize their value as bulbs, then pay the disposal cost anyway.

You end up trashing many lamps anyways during a group re-lamp. If business interruption and labor cost was zero, each lamp would be used up until they fail.

20,000 hours mean that if you've got 1,000 lamps going on, random 500 will be out by then. In real life, you can only get to about 70% of life, because there's no way that letting half the lamps go out is acceptable if group relamp is the method used.

If you have a stockpile of new old stock T12s, donate them to Habitat ReStore and get a tax deductible donation credit.
If you don't have much spare lamps, keep an eye out for available incentives, then make the retrofit that takes advantage of those when its convenient for you, for example, slow season of business when project would have minimal business interruption.