Replacing fluorescent tube with LED

[MyNameIsUrl]

I can’t get the new LED tube to work. I’ve replaced the starter with a ‘LED fuse’. I’ve opened up the fitting to check if that’s faulty but as far as I can tell there is voltage where I would expect it to be, although I don’t understand the need for 4 terminals.

Now I’ve just noticed the new LED tube has L and N marked at one end, so I’ve tried it in every orientation but still not working. Do I need to rewire the fitting? Have I bought the wrong tube?

[Laughton]

Bear in mind that I'm not an electrician but when you say a new LED tube, do you mean you've bought an LED tube that is designed to fit into your existing fluoresent light fitting?

I fairly recently replaced all (12) fluoresent lights in our garage and lofts with all in one LED light fittings (I think they're called battens). They look nicer, give off much more light, fitting was super simple and hopefully much cheaper to run.

The ones I used are no longer available but similar, I think, to these (other makes and models are available): -

https://www.screwfix.com/p/lap-single-5 ... 240v/667pp

[MyNameIsUrl]

Bear in mind that I'm not an electrician but when you say a new LED tube, do you mean you've bought an LED tube that is designed to fit into your existing fluoresent light fitting?

Yes, that's it exactly. The old fluorescent tube flickered and flashed and one end of the glass was blackened, so I wanted to replace it with a LED tube which uses less energy.

[eepee]

I bought a couple of these:-

https://www.lyco.co.uk/v-tac-50w-cool-w ... gLSXPD_BwE

As replacements in a kitchen.

Once fitted, I had to remove one - it was way brighter than the original two flo tubes!

Regards,
ep

[Tedx]

I have an LED stoplight in my loft. Flip the switch and it's like a nuclear weapon going off.

There are no dark corners in my loft anymore.

[DrFfybes]

I fairly recently replaced all (12) fluoresent lights in our garage and lofts with all in one LED light fittings (I think they're called battens). They look nicer, give off much more light, fitting was super simple and hopefully much cheaper to run.

You might be surprised. I replaced a 6 foor Fluorescent with an LED batten and the difference was about 20%, although the LED was £20 rather than under a fiver. IIRC it was a General Electric or similar well known brand.

It lasted about a year, so I put a traditional one back in.

However they are improving, a 4 foot LED batten is 36W (they're about 9W/foot) and about 3500 lumens. A 1200mm LED batten tends to be about 18W but are circa 2000 Lm, so similar lumens/Watt. However the new slimline battens only emit light in one direction unlike a traditional tube, so the lower output often provides as good illumination.

Back to the OP...

As for whether you need to rewire, look at the ballast/driver in your existing fitting and Google the model and see what type it is (magnetic or electronic) as one type can need modifying.

[csearle]

I can’t get the new LED tube to work. I’ve replaced the starter with a ‘LED fuse’. I’ve opened up the fitting to check if that’s faulty but as far as I can tell there is voltage where I would expect it to be, although I don’t understand the need for 4 terminals.

Now I’ve just noticed the new LED tube has L and N marked at one end, so I’ve tried it in every orientation but still not working. Do I need to rewire the fitting? Have I bought the wrong tube?

One I recently replaced said in the instructions that it wasn't suitable for all fluorescent light fittings. I installed it. It didn't work. I swapped ends, still didn't work. I too noticed that it had an L and N at one end. After a bit of fiddling about with a continuity tester I decided to simply connect the L and N respectively to line and neutral. New LED "tube" lit up.

So I just rewired the fitting's innards to ignore the electronic ballast inside and supply the LED "tube" instead.

Chris
PS I think the remaining two terminals are to complete the circuit so that the LED "tube" can hope to work in fittings with older ballasts.

[MyNameIsUrl]

So I just rewired the fitting's innards to ignore the electronic ballast inside and supply the LED "tube" instead.

Thanks Chris, so just to be clear you just took the live and neutral entering the enclosure and rearranged them to one 'socket' end of the fitting? Obviously preserve all the earths, but as simple as that? I guess I won't need the 'LED fuse' which replaces the starter either?

[csearle]

So I just rewired the fitting's innards to ignore the electronic ballast inside and supply the LED "tube" instead.

Thanks Chris, so just to be clear you just took the live and neutral entering the enclosure and rearranged them to one 'socket' end of the fitting? Obviously preserve all the earths, but as simple as that? I guess I won't need the 'LED fuse' which replaces the starter either?

Well that is exactly what I did, yes.

My fluorescent didn't have a starter so I didn't have one to replace. Is it really a "fuse" or are the terminals just linked together (which will ultimately be a fuse at some current I realise, but you know what I mean)?

Even if it is a fuse, the lighting circuit will be on a 6A trip switch* so I wouldn't lose any sleep over it. If you are concerned then you could rewire it to supply the LED "tube" via the "dummy starter".

Chris
* Could, less commonly, also be a 10A trip switch or a 5A fuse.

[quelquod]

Others’ experiences likely differ but my experience with LED battens is pretty poor. Out of 10 6’ battens 3 needed replacing inside a few months due to flashing periodically after they’d been on for a few hours. 3 different makes (all Chinese though I guess). Same problem with all of them which was the power supply tripping in and out probably due to overheating. All replaced under guarantee so just a nuisance rather than real cost. The power supplies concerned have no obvious way to dissipate heat with the plastic construction so maybe a bit of aluminium under them might fix them - the vendor wasn’t inclined to pay for their return postage so I’ll experiment. On the plus side when they work they are really bright partly because (as mentioned earlier) they aren’t omnidirectional.

As a by the way I’ve had problems with some of the fancy filament-style lamps too (mostly 100 watt equivalents) where one or more strands have failed dimming the light considerably. With their cost it doesn’t take long to erode the hoped-for energy cost savings!

[MyNameIsUrl]

Is it really a "fuse" or are the terminals just linked together

Out of curiosity I just opened it up - there's a tiny glass fuse marked 250mA 250V which seems enough for a 14W lamp

[csearle]

...due to flashing periodically after they’d been on for a few hours. 3 different makes (all Chinese though I guess).

Have you checked it isn't Morse code? These guys might try anything. C.

[csearle]

Is it really a "fuse" or are the terminals just linked together

Out of curiosity I just opened it up - there's a tiny glass fuse marked 250mA 250V which seems enough for a 14W lamp

Interesting. In that case I'd wire it in if I were you. C.

[jaizan]

Now I’ve just noticed the new LED tube has L and N marked at one end

This is normal. Throw away the old fitting.
Brown/Red to L, Blue/Black to N and it should work. If there is any doubt about the light, test it by wiring it to a 3-pin plug instead.

A little care is needed with light fittings, as at the ceiling, you tend to have the ring main & a live & neutral going off to the switch. It's easy to get wrong if not paying attention.

[Mike4]

Now I’ve just noticed the new LED tube has L and N marked at one end

This is normal. Throw away the old fitting.
Brown/Red to L, Blue/Black to N and it should work. If there is any doubt about the light, test it by wiring it to a 3-pin plug instead.

A little care is needed with light fittings, as at the ceiling, you tend to have the ring main & a live & neutral going off to the switch. It's easy to get wrong if not paying attention.

I can't help but suggest you re-think this bit!

[csearle]

A little care is needed with light fittings, as at the ceiling, you tend to have the ring main & a live & neutral going off to the switch. It's easy to get wrong if not paying attention.

At the risk of being picky, lighting circuits are never "ring mains" they are radial circuits and, when the lighting circuit from the consumer unit is present at the light fitting, the cable that goes off to the switch won't have a neutral in it, but rather a permanent live going down and a switched live coming back up, aka a switch-drop.

(But I agree with you that a little care should be taken as the switched-live coming back up from the switch is usually on the blue (or black) insulated conductor.)

C.

[Mike4]

A little care is needed with light fittings, as at the ceiling, you tend to have the ring main & a live & neutral going off to the switch. It's easy to get wrong if not paying attention.

At the risk of being picky, lighting circuits are never "ring mains" they are radial circuits and, when the lighting circuit from the consumer unit is present at the light fitting, the cable that goes off to the switch won't have a neutral in it, but rather a permanent live going down and a switched live coming back up, aka a switch-drop.

(But I agree with you that a little care should be taken as the switched-live coming back up from the switch is usually on the blue (or black) insulated conductor.)

C.

I'm always surprised that using ordinary T&E cable for the switch drop is permissible given the confusion sometimes caused by using the black or blue as a live conductor.

Special cable with say, brown and grey insulated conductors and an earth should be made for switch drops, in my opinion as a gas bod!

[88V8]

(But I agree with you that a little care should be taken as the switched-live coming back up from the switch is usually on the blue (or black) insulated conductor.)

I'm always surprised that using ordinary T&E cable for the switch drop is permissible given the confusion sometimes caused by using the black or blue as a live conductor.
Special cable with say, brown and grey insulated conductors and an earth should be made for switch drops, in my opinion as a gas bod!

One can put red sleeving on the black, or red tape. I sometimes do, more so in j-boxes where it can get really confusing.

I remember getting well confused when wiring my previous garage, ended up with several incandescent fittings in series and couldn't understand why they were all so dim.

Regards LED battens, I have seven in my garage/workshop, since 2016, none has needed replacing. There is one surviving fluorescent that I keep in there for nostalgia, its glow-worm emissions a link to an ancient world.

V8

[csearle]

Special cable with say, brown and grey insulated conductors and an earth should be made for switch drops, in my opinion as a gas bod!

They do sell twin and earth with two browns in it for switch drops but this would mean hauling yet another drum of cable all around Kent and Sussex. More convenient to sleeve up the blue with a bit of brown sleeving.

If you had brown and grey then you should still sleeve up the grey as it is reserved for three-phase.

C.