2D bulb question

Oops just found data sheet on TLC (how did I miss that first time I looked?). Confusingly Compton (at least) do 2 and 4 pin in both sizes.

The four pin tubes are just conventional fluorescent tubes bent up. ie from days of yore. I expect they will be phased out at some point.

The two pin ones incorporate the starting gear in them, ie they are equivalent to a CFL

They're all available in 2-pin and 4-pin versions (and you missed 10W, although it's getting rare now).

on 20/12/2012, Andrew Gabriel supposed :

They can in theory, but that was the whole point of the 2-pin type, which reduces the luminare and maintenance cost in this simple case.

You need to order the ones which match the power rating of the ballast, not the physical size. The ballast determines the power the lamps run at. You can't just stick in a bigger one or smaller one (it might work, but it might give significantly reduced tube life and/or overheat the ballast). Obviously, also needs to match the 2-pin or 4-pin fitting too.

Thanks, will check ballasts before fitting anything. Local DIY shop just stocks one wattage for each size (and is expensive).

B&Q stock both the 16W and 21W, although they are now energy saving versions (GE Wattmiser) which run slightly underpower.

The original 2D lamps don't meet future EU requirements for energy efficiency of fluorescent lamps, and I presume these have been introduced in order to keep 2D lamps available.

Normally my shed of last resort, but when I get round to getting an "Old Fart's Wednesday" card I suppose I might use them more.

Not mad on 2D, but I quite like the Screwfix "glass dome" luminaire for kitchens. Shallow, reasonably bright, easy to clean, design which doesn't really date.