Hi all, sometimes i see fluorescent values like 17W, 34W, 10W, etc...
How about listing ratings and list if they are retrofits?
(i'll update table everytime i can)

W	Current	Size	Length (mm)	Retrofit
110W (HO)	n.d.	T12	2400mm	N/A
100W	n.d.	T12	2400mm	125W T12
58W	0.67A	T8	1500mm	YES, 65W T12
51W	0.7A	T8	1500mm	YES, 58W T8
40W	n.d.	T12	1200mm	n.a.
36W	0.44A	T8	1200mm	YES, 40W T12
34W	n.d.	T8	1200mm	YES, 40W T12 (American RS only)
32W	0.448A	T8	1200mm	YES, 36W T8 (EU ONLY)
30W	N.D.	T8	n.d.	n.d.
20W	n.d.	T12	600mm	n/a
18W	0.36A	T8	600mm	YES, 20W T12
16W	0.38A	T8	600mm	YES, 18W T8
15W	n.d.	T8	n.d.	n.d.
10W	n.d.	T8	n.d.	n.d.

Note: all length are metrical!
Thanks to:

• dor123
• Medved
• Roi_hartmann
• HU112

The 58W T8, is a retrofit only in the UK, as they are the only country to have 65W T12. Here in Israel, 58W isn't a retrofit tube, since we had only T12 of 20W and 40W and the american high output T12 of 110W 2400mm
The americans have the 34W T12 1500mm lamp, to retrofit their 40W T12 on their rapidstart ballasts, I don't know what is the lamp current.
The britishes have the 100W T12 2400mm lamp, to retrofit their 125W T12. 58W is a retrofit of 65W and 80W T12 in the UK.

thanks dor123!
58W are common across Europe.

The retrofitting works only on some ballasts (although that could still mean the vast majority of use of that bulb in a given area), it is not universal at all.
That was one of the reasons, why e.g. in the US the F36T8 was not adopted, but the market went directly to fully incompatible F32T8 - as the F36T8 is compatible with the F40T12 only on a preheat ballasts, but those were long time "abandoned" in the US...

the thing about the f34t12 tubes used as retrofit tubes is that some ballasts that arent rated will get cooked or (miraculously) survive. it is not advisable to use the f34 tubes on tulamp or preheat ballasts either, as they will also overheat and cook the ballast.

it is not advisable to use the f34 tubes on tulamp or preheat ballasts either, as they will also overheat and cook the ballast.

Can you explain that, please?
what is tulamp?

F34 tubes draw more amps, therefore driving the ballast to extreme limits, possibly burning out the coils or caps. Tulamp ballasts are vintage lead lag ballasts. The lead lag circuit consists of an autotransformer and the ballast could. It also has a cap, which is part of the circuit and then one for the power factor.

There is also European energy saver lamps to replace standart 18w, 36w and 58w T8 lamps. wattages are 16w (0,38A), 32w (0,448A) and 51w (0,7A). These are only meant to be used with preheat ballast. some model names are LUMILUX T8 ES and Master TL-D Eco.

I've also seen preheat American ballasts listing 16 watt lamps as ok to use.

It also has a cap, which is part of the circuit and then one for the power factor.

The cap in the lead circuit is already compensating the phase from the lag circuit, so it is intrinsically high power factor, so there is no need for any separate capacitor just for the power factor correction.

However small capacitors are used for RF supression, but those are not the main functional components.

F34 tubes draw more amps, therefore driving the ballast to extreme limits, possibly burning out the coils or caps. Tulamp ballasts are vintage lead lag ballasts. The lead lag circuit consists of an autotransformer and the ballast could. It also has a cap, which is part of the circuit and then one for the power factor.

does it have sense?
Ballast limit current flow, so how they can "draw" more amps?

The thing is, f34 tubes are designed exclusively for rapid start, and some of the older ballasts aren't compatible due to them being relatively new. Preheat ballasts will either not work (glowing at the ends) or fire the tube up and run it dim and cook the ballast.

The F34 have a lower lamp voltage due to the use of krypton gas filling, so more current passes through the ballast as a result, therefore overloading it. Old rapidstart ballasts which aren't capable to withstand that higher current, would burn their windings or got shorted.

Thank you, dor, that is what I was trying to say. Just use f34t12 tubes on rated ballasts and you're golden.

The ballasts are indeed a constant current sources, but still not ideal current sources. So the current fed into the lamp does slightly depend on the lamp arc voltage. So e.g. when a F40T12 ballast feed 0.43A into the 100V arc F40 tube, it may get to about 0.47A into the 80V arc F34 tube. The current difference seems to be not that large ("just" 10%), you should not forget the power dissipation is proportional to the square of the current, so it will be about 20% higher. Even that does not seems to be that much, but if you think of temperature rise (the difference from the ballast core to the ambient), that is proportional to the power dissipation, so it will be 20% higher as well. Now if we take standard ballast designs, designed to with temperature rise of 50degC, it means the temperature will rise further by about 10degC. And that means about 2x shorter lifetime when the life would be fully limited by just effects corresponding to the diffusion rate equation (all chemical reactions, varnish degradation,...).
That is the reason, why you should never exceed any choke current rating e.g. when using for building a ballast for some another lamp...