Flourescent tube.

[scooby1]

I have looked for an answer but couldn't find one so asking what I hope will be a simple problem to solve. I have a flourescent light fitting in my office and it has an Osram 120cm T8 L36W827 Warm White tube in it. But it is very dull and I want to replace with something brighter and so my questions are :

1. I know that T8 means that the light is 1" in diameter. (I presume that is the diameter of the tube and not the end fittings ? ) Can I substitute the T8 with a T12 (I assume that being larger I will be able to get a brighter light ?) Do they all have the same diameter fittings on the end ?

2. I remember having to replace starters sometimes in flourescent lights but now there seems to be something called a ballast <sp> Will whatever starts the tube at the moment start a T12 ?

3. I am under the impression that wattage is the electricity used and lumens is the brightness but not all bulbs show the lumens no. I'm a bit confused about that.

4. I hope I am asking the right questions but if anyone feels like just telling me to go and buy a XYZ tube then please feel free to do so.

And thanks in advance to all who can and do help.

 

[333rocky333]

Dump the tube and fit a T8 36watt the same but get colour 840, it will be better than you have and still be better and cheaper than a T12 40watt

1, T8 and T12 are both G13 that is 13mm between pin centres.

2, Electronic ballast, if you have that, are designed for36 watt T8, a T12 would be 40w so not right

 

[winston1]

T12 tubes are obsolete and difficult to find. Has it always been too dull? The reason I ask is because florescent tubes get dimmer towards the end of their life so it could just be a new tube required.

Otherwise upgrade to a 150cm T8 58 w fitting.

 

[scooby1]

Dump the tube and fit a T8 36watt the same but get colour 840, it will be better than you have and still be better and cheaper than a T12 40watt

1, T8 and T12 are both G13 that is 13mm between pin centres.

2, Electronic ballast, if you have that, are designed for36 watt T8, a T12 would be 40w so not right

Thank you for that @333rocky333 . Yes, I thought that the pin centres were about 13mm. But now I need to do a bit more investigating because I've just remembered that the original light was a single pendant bulb when we built the house 8 years ago and I changed it for this flourescent tube that's up there now and haven't got a clue where it came from. Maybe I need to buy a complete new light unit.

 

[scooby1]

T12 tubes are obsolete and difficult to find. Has it always been too dull? The reason I ask is because florescent tubes get dimmer towards the end of their life so it could just be a new tube required.

Otherwise upgrade to a 150cm T8 58 w fitting.

Thank you @winston1. On reflection yes, it has never been very bright but as per my post above, maybe I stupidly fitted the wrong light anyway because it was just one that I had in stock and I thought that it would do the job. My office is 4.8mts x 2.9mts-ish. Is there a formula for what is deemed to be the correct tube in that scenario ?

 

[Keithmac]

I've just changed our 4ft florescent tube for an LED, straight fit with new "starter".

Night and day different.

 

[scooby1]

I've just changed our 4ft florescent tube for an LED, straight fit with new "starter".

Night and day different.

Thanks for that @Keithmac . I have an account at Screwfix which is where you got that from. Do they do the starters if I need one ? And what am I looking for in the unit as far as starter and ballast is concerned. Sorry for the ignorance but I'm not an electrician.

 

[Keithmac]

This came as a kit, you fit the LED tube as a direct replacement for the florescent tube and it comes with a starter replacement in the box.

You have to fit the new starter.

Not as cheap as a normal tube but very good light output.

 

[winston1]

This came as a kit, you fit the LED tube as a direct replacement for the florescent tube and it comes with a starter replacement in the box.

You have to fit the new starter.

Not as cheap as a normal tube but very good light output.

But only any use if you have a traditional ballast and starter. You cannot use this with a starterless system without completely stripping out the existing ballast.

 

[flameport]

My office is 4.8mts x 2.9mts-ish. Is there a formula for what is deemed to be the correct tube in that scenario ?

At a very basic level, lumens (light output from the tube) divided by floor area = lux level.
A 36W fluorescent tube should be about 3350 lumens, your office 14m², about 240 lux assuming even illumination and no losses. Will be significantly less in reality, and even 240 lux would be considered very dim for an office. 500 lux would be more usual.

A 4.8m long room isn't going to be properly illuminated with a single light source of any kind, two or more are required for even illumination.

 

[Taylortwocities]

Also remember that light at floor area will reduce the higher the ceiling is!
Direct floor illuminance is inversely proportional to the height of the ceiling (not counting reflection)

 

[FrodoOne]

This came as a kit, you fit the LED tube as a direct replacement for the florescent tube and it comes with a starter replacement in the box.

You have to fit the new starter.

Not as cheap as a normal tube but very good light output.

That replacement "Starter" is actually a Fuse.

I recently installed several replacement 1200 mm Osram "SubstiTUBESs" - 16 W, 2200 lumens.

https://www.osram.com/ds/ecat/Subst...s/com/en/GPS01_1373277/PP_EUROPE_Europe_eCat/

 

[scooby1]

Thank you all for your help. I think I need to dismantle the lamp and see what I have got inside it. As I said earlier, I'm not sure where the lamp came from, it could easily be 20 years old and just have the old type of starter. Piccies to follow.

But I am tempted to just go and buy another complete unit, probably a longer one. It's my office so I don't mind spending a bob or two !

 

[Taylortwocities]

Does the light flash once or twice before it comes on? If so you have the old type of starter.

But really, treat yourself to a whole new fitting.

 

[scooby1]

Does the light flash once or twice before it comes on? If so you have the old type of starter.

But really, treat yourself to a whole new fitting.

Thanks @Taylortwocities, it sort of flickers for a couple of nano seconds, it doesn't flash as such like they used to do years ago. I'll still have a look inside it just out of curiosity but you may well be right with the new unit idea.