I always advise that machine control circuits should not be colour coded for precisely that reason. The colour coding on T & E is really for the convenience of the installer and can be misleading to anyone else who might be unaware of junction boxes etc.
Is a sticker required on the Consumer Unit??
- Thread starter Submariner
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IIRC if run at 70°C 100% of the time the life is expected to be 20 years, and there's a formula I've seen for working out the expected life for different duty cycles.
I'm sure that anyone who does EICRs will attest to the fact that 40-50 year old cables in service are often perfectly OK.
I'm pleased to hear that I'm improving!!Better, John!
Agreed - but twin red (or twin brown) never seems to have been used all that much. Talking of which, I saw something particularly daft fairly recently - switch drops wired in red/black singles. Little excuse for that! Having said all that, I suppose there is some utility in having an identification of which is L and which is SL - maybe we need some additional colours! I must say that, in terms of old colours, I got very used to a convention (usually in relation to more 'unusual' wiring situations) of having red for L and yellow for SL with 3C/E cable.
Kind Regards, John.
No! We need to educate people to stop assuming that they know the function of a conductor from its colour!
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Indeed - but as with all long-term life expectancy estimates, that necessarily relies on potentially iffy extrapolation from relative short-term testing (at least initially).
I'm also sure of that. Indeed, I have some such cable (stranded imperial PVC) still in service in my house, and it tests fine.
Kind Regards, John.
Not even if documented?
Just imagining what a nightmare working on car wiring would be if it were not colour coded...
As I'm sure you realise, it wasn't a serious suggestion! However, adequate identification of conductors and cables (particularly at downstream ends), quite apart from the colours, is something that doesn't seem to get anything like as much attention as it could (should?) - at least in most domestic installations.
Kind Regards, John.
But just imagine how much easier and safer it would be if every conductor was uniquely numbered at each end.
At each end?
What if you needed to identify cables at points other than the ends?
And you'd still need to refer to documentation to see how in that particular car they differentiated 6 & 9 (and possibly 18/81).
What if you needed to identify cables at points other than the ends?
And you'd still need to refer to documentation to see how in that particular car they differentiated 6 & 9 (and possibly 18/81).
Why would you need to identify conductors other than at the ends? Scotchloks might be acceptable on a car I suppose, but they're not ideal, and certainly aren't good enough for 230V domestic wiring.
Yes, of course you'd need to refer to the documentation, and I'd expect the manufacturer to use 6 and 9 where there is no accompanying letter. There's an IEC standard on the subject of conductor and cable identification by alphanumeric lables, whose number escapes me at the moment.
Are your hot water pipes a different colour from the cold? Or, come to that, from the gas pipes?
To break into them.
OK - probably the reasons for doing that these days are less common than they were decades ago, but you might, and it's a factor against only identifying cables at the ends.
And against digital control circuits, but there's not much to be done about that.
There are always alternatives to those nasty things.
The numbers, proximities and traceability of gas and water pipes in a home are so different from car wiring looms that it's pointless trying to draw analogies.
Maybe not so different from a simple domestic wiring installation though, so I think it illustrates my belief that you don't actually need colour coding in many systems.
Care to explain how, armed with reels of multicore cable, all cores the same colour, someone would go about installing even simple domestic wiring?
The problem with cables only being identified at the ends is that when you cut a length off a reel then at best only one end is identified, so what do you do at the other end?
The problem with cables only being identified at the ends is that when you cut a length off a reel then at best only one end is identified, so what do you do at the other end?
Inadvertently I think you have argued against yourself and, conversely, confirmed the pointlessness of the said stickers.
It depends on what you mean by 'most' (51% to 99%) but accepting it will be at the higher end, it further renders the stickers pointless as 'nearly all' installations will require one and so, in reality, it should therefore be assumed that an installation will likely contain wiring to both sets of colours.
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