In article ,
Mike writes:
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.

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.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]