Confusion over lengths of T4 fluorescents

[Richard Russell]

This is more of a rant than a question... Why are there two similar (but incompatible) lengths of 20W T4 slimline fluorescent tube - the so-called 'Eterna' variety (as sold by B&Q) which is 578mm between the ends of the pins, and the 'Standard' variety which is 567mm between the ends of the pins?

I'm finding it difficult to obtain replacements - at a sensible price

- for the latter size (567mm inclusive) with 3400K colour temperature. TLC only do 4000K..... grr!

Richard.

reply by email change 'news' to my forename.

[NOSPAMnet]

length and wattage but doesn't say Col Temp

[Richard Russell]

Yes, I'd already found that and I've emailed them about the colour temp. They're still twice as expensive as TLC's 4000K ones though....

Richard.

reply by email change 'news' to my forename.

[BigWallop]

Just having a look at most of the sites advertising these. It's cheaper to buy a whole new fitting than just the lamp on its own. How can that be viable?

This is the cheapest price I can find online

good?

[BigWallop]

Any good?

Apologies. Here's a better on for ya

eBay always to the rescue. :-)

[Richard Russell]

Not this time. The photo shows the 'Eterna' variety (567mm between the end caps, not inclusive). That's one of the stupid things, they

*both* have a 567mm dimension, it's just a different dimension....

Richard.

reply by email change 'news' to my forename.

[Andrew Gabriel]

There aren't any standards for T4 tubes, unfortunately. Most fluorescent tube sizes were developed and standardised in Europe and the US. T4's came from the far East, and there are different ones from different manufacturers.

I've got a number of Omicron fittings which were sold by CPC, Maplin, and some other places. AFAIK, these are no longer available. I've got a stock of 16W tubes, and one spare 8W and one spare 20W. When I run out of one of the sizes, I'll probably have to replace the lot (as I won't be able to get any matching colours). More recently, I've fitted the newer T5HE and T5HO tubes (14W to 80W) as these are standardised, and lengths match common kitchen unit widths (actually they're designed to match modular ceiling tile sizes, but it amounts to the same thing).

[ARWadsworth]

,

And different ones with the same manufacturer!

Three undercupboard lights, all by the same manufacturer. Two of the tubes were smashed before I installed the fittings.

I went to the wholesalers and bought three replacement lamps so that everything matched. One of these replacements did not fit in any of the fittings and the other two were different colours. All three had the same manufactures name number and colour stamped on the glass and were in identical boxes.

Aurora made the tubes in case you wanted to ask:-)

Ask

[Mike]

You've obviously measured yours but catalogue listings are often completely wrong. Screwfix seem to measure tubes by overall length including the packaging rather than the tube length, or the length including pins.

For instance 91349 36W T8 - a "4ft tube" is listed as 1283mm long,

51944 an economy 36W T8 is apparently over 3 inches shorter at 1200mm long - in most cases the actual tube is circa 1210mm long including the pins, a gnats under 4ft.

[Andrew Gabriel]

4', 5', etc are actually how long the original fluorescent fittings were (for when you installed them in a line). That's not a very useful measure of the tube length, nor indeed the fitting length of a new fitting you might buy today. Original tubes had bayonet lampholder caps with the lampholder on flying leads, so tube length wasn't critical to hold the tube in.