Connecting a 2D bulb

10 Jan 2019
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United Kingdom
Having replaced the 2D bulb in a kitchen wall light and finding it still didn't work, I'm trying to fit a Tridonic PC 1x26W BASIC ballast. This replaces the original ballast where the bulb plugged directly into it which I'm told is no longer available. However I can't get it to work when I connect the four bulb terminal pins to the same numbered terminals (1-4) as on the original ballast? I also understand that the two mains feed wires can be connected either way round?
Any advice would be much appreciated. Thanks
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I think you are probably flogging a dead horse. Time to change the entire fitting to LED. Toolstation, Screwfix TLC and others have a range of ceiling/wall fittings to choose from.
Not sure what your trying to do, 26watt ballast is not normal for a 2D lamp.
With the correct ballast terrminal 1 and 2 will go to the two pins to the left of the lamp and terminal 3 and 4 will go to the two pins to the right side, hence the two sides form a 2D shape, think off it as a normal tube bent into shape with 2 pins at each end.
The supply can go either way round as you say, but the casing if metal should be earthed or bolted to earthed metal.
The ballast should be 16, 18, 28,38,55 to match the lamp wattage.
Photos would help
333Rocky333 - followed your advice and yeah .. the horse lives and we have light. The casing is properly earthed and I now just need to house the new ballast within the old ballast casing so I've got a way of plugging the bulb in .. a job for tomorrow and I'll post a pic to show the result. Very many thanks!
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A Tridonic PC 1x26W BASIC will run a 28w 2D lamp, which is the lamp you should have fitted. Any other wattage is either going to kill the ballast or lamp prematurely.

There is no point changing to LED from T5 HF IMHO.
Job done, thank you for the replies.


  • Original ballast.jpeg
    Original ballast.jpeg
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  • New ballast installed in original cover.jpeg
    New ballast installed in original cover.jpeg
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That's how it was when I moved in. In practice, is it likely to cause a problem??
Both the original Kengo (they're crap, BTW) ballast and the replacement ballast you've fitted are for a 28w 2D lamp. Best guess is the '16w max' sticker is erroneous

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