Current carrying capacity of the wires inside a fluorescent batten with regard to LED tubes

Are you concerned at the current carrying capacity, or the voltage rating ? I see no cause for concern regarding voltage rating or current.


The wire commonly used has a cross section of at least 0.5mm and sometimes more. Common sense, previous experience, and comparison with other wires suggests a current carrying capacity of at least 6amps. The current used by the replacement LED tube will be a fraction of an amp and almost certainly less than the current used by the originally fitted fluorescent lamp.


As regards voltage rating, IIRC this wire is rated at 600 volts. And whilst I can not substantiate this, common sense and experience again come to the rescue. The wire must be considered safe for at least full mains voltage since most of the internal wiring is potentially subjected to at least full mains voltage when used with originally intended fluorescent lamp. A switchstart ballast can produce pulses of a thousand volts or more, and an electronic ballast can produce up to a few hundred volts.


In short, fitting a LED replacement lamp, wont increase either the voltage or the current beyond that originally intended.

I'd agree that 0.5mm² (1/0.8mm dia) is commonly used - normally with heat resisting insulation.


Current carrying wise in normal service it'll be fine. For fault currents it's probably not so (especially where the fitting doesn't include its own local fuse) - but then you'd probably be expected to replace the entire fitting anyway if it ever did go "bang" - so the internal wiring being a write-off isn't really of any consequence.


   - Andy.

@ broadgage   -  thank for the reply.   I was just interested in the current carrying capacity - sorry for any confusion or if it came across as a bit silly, but there you go :-)


It's just interesting to me at least, with regard to reusing the wires and altering the insides etc, what the ccc was likely to be (I couldnt locate any info from a brief search on t'interweb) for one aspect - of course the tube wont draw a lot, but curiosity developed from a overload/protective device point of view I suppose. Cheers.

@AJJ thanks for that.  You have touched on what was in my mind in my perhaps poorly worded question.   I was writing in response to the previous post and then noticed your response.


It just seemed a good idea to try find out what those internal wires were rated at etc.   Thanks [both] for the response.

It's certainly an interesting discussion.


Unless the mod kit is made by the original luminaire manufacturer, AND they also say it's suitable for that specific model of light fitting, the responsibility for the luminaire after the modification (in particular, its safety and EMC compliance) most likely lies with the person (individual or organization) carrying out the modification.


I'm sure under these circumstances, original equipment manufacturers would be quick to point that the luminaire no longer complied with the original specification, should something unpleasant happen after the mod.

@gkenyon -  yes I think one has to conclude that the OEM certifications are void.


Most LED tube kits either make use of the internals as they are (no mods) when a magnetic ballast and starter are present (just using a replacement starter) ie. just fit the tube.


If electronic internas (no starter/electronic ballast) then everything has to be removed and the LED tube itself is the only active component.


In both cases I think the LED tube manfacturers instructions for the product and fitting become relevant and the batten is just a mounting facility for the LED tube - which the manufacturer, one would presume, is stating is suitable for their product when their instructions are followed.


The wires being resused in the batten just need to be verified as suitable in my view - electrically - as the supply to the LED tube.

psychicwarrior:

@gkenyon -  yes I think one has to conclude that the OEM certifications are void.


Most LED tube kits either make use of the internals as they are (no mods) when a magnetic ballast and starter are present (just using a replacement starter) ie. just fit the tube.

So, if just replacing a starter and the lamp, then perhaps OK, but I don't think either manufacturer would take full responsibility.

• The manufacturer of the lamp would say it was never designed for that starter and tube?

• The manufacturer of the replacement lamp and starter gear only made that?

If electronic internas (no starter/electronic ballast) then everything has to be removed and the LED tube itself is the only active component.

In both cases I think the LED tube manfacturers instructions for the product and fitting become relevant and the batten is just a mounting facility for the LED tube - which the manufacturer, one would presume, is stating is suitable for their product when their instructions are followed.

The wires being resused in the batten just need to be verified as suitable in my view - electrically - as the supply to the LED tube.

BTW, RS stock this wire, part number 183-9225 for white, also available in blue, brown, and green/yellow. Also useful for other purposes when ever a small rigid conductor is needed.


It is also manufactured in pink, violet, orange, grey, very light blue and very light brown, but RS only stock white, brown, blue and green/yellow.

Interestingly, BS EN 60445:2017 and IEC 60445:2017 changed the preferred usage of White from "could be an option if you don't want to be specific" to "DC -".

Some of the instructions detailing how to convert the fluorescent fittings to LED tell you to install a fuse holder and fuse, others tell you to replace the starter with a fuse they supply for the purpose.


It isn’t the current that the LED replacement lamp you need to worry about, it is the current that will be drawn if someone takes that out and puts a fluorescent tube back into the fitting.


Andy Betteridge