I am having a conversation on another forum about converting fixtures from CFL to proper fluorescents. By proper fluorescents i mean Tx, PL-x and 2D

Now 2D, PL-C, PL-D and PL-L work properly on magnetic ballasts. But what about PL-T ?

I see that most PL-T's are 4 pin, so dont contain internal starter, so perhaps are only meant for electronic

What are the common PL-T sizes ?

Are they meant for use with electronic only or for either ballast type ?

Which of them can (even if it is not rated by the manufacturer) run on (which ?) PL-C/D or T8 magnetic ballast (240V here) ?

Is it reliable ? And do they last up to their rated life in this condition ?

Generally except the stating stress, the HF operation wear the fluorescent lamp way less than the 50/60Hz, so on any magnetic ballast I would expect shorter tube life than on a decent programmed start (or any, if the burn time per switching cycle is very long).

These modern tubes are thin, what mean they are quite hard to ignite (and so have quite high reignition spikes related to the current zero cross).

What I noticed, majority of these lamps are designed along T5HO or T5HE spec's, so they may share the ballasts. Beside the ignition, the operation would be similar as the T5's. Again, the rule is arc voltage<=(Vmains/2) and it may need an electronic starter with time out (as the reignition spikes tend to trigger the starters)

The lamps are 4 pins mainly to be compatible with an electronic ballast, but it does not mean they are not compatible or even in some cases rated for a magnetic ballast, only require separate starter. Already few years a directive mandate all new fluorescent lamp types to be compatible with HF ballast. Technically would be possible to make even the 2-pin lamps (with an integrated starter) compatible, but that would require very detailed exact standardization of the ballast parameters, as the resonant capacitor would be part of the lamp and not the ballast, while it should match the ballast's other components (coil, frequency,...). So makers have chosen the easier way - make lamps without the starter. Then the capacitor is part of the ballast and it is designed with other components to the given frequency and voltages inside and when someone want a magnetic ballast, the external starter may be still used.