LED retro-fit tubes

[says-les]

Crompton 4 ft LED tubes cost £!2 and come with an instruction leaflet and a starter switch.  I believe this starter is simply a short inside.  I fitted four in a 4ft by 2ft modular luminaire last week and all was fine.

A friend bought the same type and was advised by the young guy at the supplier sales counter that he would need to rewire the internal wiring of the switch start luminaire which he did and that was fine.

This non-technical friend was adamant that the instruction leaflet stated that the mains had to be taken to one end of the tube directly and the correct end of the tube connected to that lampholder.Fluor Cct.pdfFluor Cct.pdfFluor Cct.pdfFluor Cct.pdfFluor Cct.pdfFluor Cct.pdfView attachment 7919

I tried to tell him that he was going to more bother than necessary, but he insisted that was the only method.

Now apart from all of this, supposing the wiring in a luminaire is altered to take the mains to one lamp holder, and some bright spark in future decides to fit a fluorescent tube in stead of an LED tube.  This would be dangerous as 230volts would be applied across the 12volt rated filament at that end of the fluorescent tube.

If a retro-fit is made in such a situation,  the choke is left in series with the lamp circuit, but only if thefar end of the lamp has a circuit through what would normally be a filament in a fluorescent lamp.

If this is correct then it won't matter which way round the lamp is fitted.

Please can the sparks out there consider this, and correct me where my thinking has gone astray?

To help in any discussion here is the standard glow type switch start fluorescent circuit.

 

[says-les]

Crompton 4 ft LED tubes cost £!2 and come with an instruction leaflet and a starter switch.  I believe this starter is simply a short inside.  I fitted four in a 4ft by 2ft modular luminaire last week and all was fine.

A friend bought the same type and was advised by the young guy at the supplier sales counter that he would need to rewire the internal wiring of the switch start luminaire which he did and that was fine.

This non-technical friend was adamant that the instruction leaflet stated that the mains had to be taken to one end of the tube directly and the correct end of the tube connected to that lampholder.

I tried to tell him that he was going to more bother than necessary, but he insisted that was the only method.

Now apart from all of this, supposing the wiring in a luminaire is altered to take the mains to one lamp holder, and some bright spark in future decides to fit a fluorescent tube in stead of an LED tube.  This would be dangerous as 230volts would be applied across the 12volt rated filament at that end of the fluorescent tube.

If a retro-fit is made in such a situation,  the choke is left in series with the lamp circuit, but only if thefar end of the lamp has a circuit through what would normally be a filament in a fluorescent lamp.

If this is correct then it won't matter which way round the lamp is fitted.

Please can the sparks out there consider this, and correct me where my thinking has gone astray?

To help in any discussion here is the standard glow type switch start fluorescent circuit.

View attachment Fluor Cct.pdf

 

[Lurch]

Not sure what your actual question is.

 

[says-les]

Sorry for being vague, but I suppose it is, "Am I correct in what I say about retro fitting and what would be the circuit diagram?  Is there danger of a short if mains is taken to one lampholder. and some one inserts a fluorescent tube instead of an LED type?

 

[bluetobits]

You are correct. The safest way is to leave the fitting wired as it would be for a standard magnetic switch start ballast arrangement so the led tube can be fitted either way round. The replacement starter is also a fuse and not just a "shorted" connection as you said. 

 

[Lurch]

Is there danger of a short if mains is taken to one lampholder. and some one inserts a fluorescent tube instead of an LED type?

Yes, but then really the fitting should be labelled and clearly identified as "for LED tubes only" or some such.

Personally I never like the idea of ripping the wiring apart to retrofit LED tubes, sort of defeats the point, you might as well just stick new fittings up at that point. I've done a few retrofit jobs and half the time the fittings are due for replacement anyway, with brittle lampholders/caps and the like I wouldn't want to start playing with rewiring them, just changing the tube is sometimes a challenge to not have half the fitting in crumbs on the floor.

 

[ProDave]

DO NOT try fitting LED tubes in HF flourescent fittings. They give a quick flash, once, then they are dead.

The shop took them back as "faulty" :innocent
 

 

[revjames]

I fit quite a few 2D LEDs they will work with or without the magnetic ballasts but more efficient without. In this case 230V wired direct to lampholder. If anyone was stupid enough to take out the LED and put a 2D back in then I guess it would go bang.

 

[says-les]

Thanks to all replies which help greatly in my understanding. I think Lurch hit it on the head by saying that replacing the luminaire is best option, from safety view point and efficiency and future maintenance.

Cheers Guys

 

[binky]

I have converted many florries to LED and wire out the ballasts for greater energy savings. Crompton tubes do come with a safety label hidden in the piece of paper with the wiring instructions on which you stick to the fitting. Andy is correct in that sometimes the lamp holders are knackered, but I haven't had too many problems with that, and you can buy LED ready fitiings - wired for mains with no ballasts etc etc. Think Fitzgerald lighting do these.

 

[Lurch]

Andy is correct in that sometimes the lamp holders are knackered

My name isn't Andy.

 

[steptoe]

My name isn't Andy.

George,?  

:C

 

[M107]

DO NOT try fitting LED tubes in HF flourescent fittings. They give a quick flash, once, then they are dead.

The shop took them back as "faulty" :innocent
 

:slap ....................

 

[rapparee]

George,?  

:C

Chicken George, Son of Master Lee, Grandson of Kunta Kinte 

 

[steptoe]

Chicken George, Son of Master Lee, Grandson of Kunta Kinte 

Kunta Kinte, that's a blast from the past, my granda used to say that all the time,

 

[rapparee]

Kunta Kinte, that's a blast from the past, my granda used to say that all the time,

The 2016 remake was on BBC 4 last night.

 

[says-les]

If you open my diagram in one of my earlier posts you will see the standard method of wiring a glow switch start fluorescent lamp.

Now what I want to know is what do we draw for the retro-fit starter and with what do we replace the non-electronic driver end of the lamp, bearing in mind that the retro-fit style lamp (and there is at least another earlier type that doesn't work as a retro-fit (mains has to be taken to the correct end).

The non-electronic end of the retro-fit lamp must allow current to flow, in order to complete the circuit, and what effect does leaving the choke in circuit have, if any? I feel that manufacturers such as Crompton have not given the trade an insight into their design. Maybe we need a technical article written by their design office. Maybe the average spark doesn't have the interest, or the time to know or to read up on this. The fluorescent Iamp circuit, and there were several, was one of the fist things to be taught to apprentices in my firm back in the early days, and it included a mention of Power-Factor correction capacitor and the small radio interference suppressor capacitor inside the starter switch. 

 

[Lurch]

what do we draw for the retro-fit starter

Depends what's in it. If there is nothing in it it is just a link, so the same as a piece of wire. Some people have said they are fused, so draw a fuse if so.

with what do we replace the non-electronic driver end of the lamp

Nothing. Just leave the unconnected lampholder there.

The non-electronic end of the retro-fit lamp must allow current to flow,

I'm confused, are we talking about the rewiring or non-rewiring type?

 

[says-les]

Depends what's in it. If there is nothing in it it is just a link, so the same as a piece of wire. Some people have said they are fused, so draw a fuse if so.

Nothing. Just leave the unconnected lampholder there.

I'm confused, are we talking about the rewiring or non-rewiring type?

The non-rewiring circuit.

 

[Lurch]

The non-rewiring circuit.

Then I'm lost again. We don't do anything with any end of the circuit, we just replace the tube and starter.