I prefer stranded singles in conduit, but insulated and sheathed solid singles are readily available for when using T&E.
Insulated and sheathed PVC/PVC single brown, single blue, brown and earth and blue and earth are all available.
Armoured cabling questions
- Thread starter DIYTom
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I prefer stranded singles in conduit, but insulated and sheathed solid singles are readily available for when using T&E.
Insulated and sheathed PVC/PVC single brown, single blue, brown and earth and blue and earth are all available.
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Interesting. Do I therefore take it that all of those are in widespread use in Ireland?
Kind Regards, John
It will be the ban on any form of oversleeving which makes 3C+E unusable.
http://www.etci.ie/news/harmonisedcablecorecolours.html
http://www.etci.ie/news/harmonisedcablecorecolours.html
Indeed - that's what Risteard said. However, rather than having to use all the various PVC/PVC singles and singles+earth that Risteard mentioned, they could have 3C+E with, say, brown/brown/brown and brown/brown/blue.
The irony is that, as I've said, whilst a prohibition on over-sleeving makes the identification of cores as L or N infallible (throughout the length of the cable), it makes identification of the function of conductors (e.g. of 2 or 3 browns) much more difficult!
Kind Regards, John
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No point - all that would do would be to make the cores harder to identify. Functionally, and used in compliance with ETCI rules, brown/black/grey does the same but avoids the identification problem. And could legitimately be used for 2-way switch strappers, had the ETCI the wit to allow it, because you may oversleeve grey and black with brown to preserve phase identification. In much the same way that we should do, and should have done in the past with red sleeving on yellow & blue cores.
Very limited applicability. Could not be used for 2-way switch strappers.
You're allowed to use sleeving or tape for identification purposes, just not to turn a line or neutral conductor or a cpc into any of the others.
Yes, I've already made that point (below) - but the same will also be true, in some applications, with brown/brown T+E, which they do use.
Pretty limited, yes, but a bit of a pain having to run two cables to a timer fan or, in some situations, to a PIR etc.
It could if one was using the 'old-style' 2-way switching, with N accompanying the two strappers - and that would also avoid the 50Hz radiation issue.
Oh, fair enough.
Kind Regards, John
Yes, but it's the limited applicability which I think is the problem.
It could if one was using the 'old-style' 2-way switching, with N accompanying the two strappers[/quote]
An even less likely scenario.
As far as I can see it is not that any of these cables are prohibited - our 3C+E cables could be used there, but it is the prohibition on oversleeving brown/black/grey with blue that makes its use cases so rare as to make it pointless for it to be on sale.
However, my reading of their oversleeving rules is that cable makers could produce a cable with orange, pink and green cores that could be oversleeved to be any of brown/black/grey/blue. It's the oversleeving of existing harmonised colours to mean something else which is forbidden.
Do you think that the applicability would be more limited than, say, the blue+earth which Risteard said was readily available, and used?
[sloppy quoting mended in my quote of your quote!!] I'm not so sure,if twin brown is being used for the strapper. Whichever 2-way switching arrangement is being used, there is likely to be a need for an additional brown, or an additional blue, to accompany them.
Are you saying that their regulations allow black or grey to be over-sleeved with brown, and/or that black and grey are acceptable identifiers of L in a single-phase installation?
Kind Regards, John
Possibly not.
But twin brown has an obvious usefulness, and I read tales of twin red being common here in the past for switch drops. So given that, a single blue makes a useful accompaniment, and blue+earth could be made on the same machines as brown+earth.
A bigger Q is why make any cables with a single core & cpc?
Sorry about that - I was rushing to get it done, and didn't check it. No excuse, but it is the reason.
But a significant enough need for 2 brown and 1 blue to make a single cable with those commercially viable?
AIUI the first is actually mandated and the second is prohibited. So you could use our 3C+E, with black & grey oversleeved with brown, for a switch strapper.
One of their rules is "Where more than one conductor in a multi-core cable is fed from the same phase, both shall be identified by the relevant phase colour, using sleeving as needed." Admittedly that's not taken from an actual regulation, so the formal wording might be better, but as written would it not mean that in a building with 3 phases supplied but with single-phase circuits installed, not necessarily originating at a 3-phase DB, that you'd have to possibly sleeve your twin brown switch drops as twin black or twin grey?
Dad had a roll of DI 1.5mm from local wholesaler in the West Midlands when he rewired the house in the mid-1980s. Especially for switch drops.
All true - but wouldn't it be equally true that brown/brown/brown or brown/brown/blue 3C+E could be made on the same machines as 'standard' harmonised-colours 3C+E?
I suppose that depends upon the extent to which one subscribes to the view that it is desirable that any cable contains a CPC, so as to afford at least some chance of a protective device operating if it is penetrated by something.
As above, I'm not sure that 'commercial viability' is necessarily much of an issue, given that occasional short production runs of such cables could be undertaken on the same machines normally used to produce the normal harmonised-colours 3C+E.
If that's the case, why don't they do it (assuming they don't - which is what Risteard seemed to imply) - it would seem (to me) to be preferable than having to run two cables.
That would seem to be the case but, as you say, the actual regulation might be worded differently. In fact, I'm not sure why they would restrict that to situations in which there are 'two or more cores fed from the same phase'. If they are concerned about phase identification (in single-phase circuits fed from a 3-phase DB), I would have expected them to also require the (single) brown of T+E to be over-sleeved (with black or grey) when appropriate!One of their rules is "Where more than one conductor in a multi-core cable is fed from the same phase, both shall be identified by the relevant phase colour, using sleeving as needed." Admittedly that's not taken from an actual regulation, so the formal wording might be better, but as written would it not mean that in a building with 3 phases supplied but with single-phase circuits installed, not necessarily originating at a 3-phase DB, that you'd have to possibly sleeve your twin brown switch drops as twin black or twin grey?
Kind Regards, John
You'd have to ask him that.
They do.
Apologies - I did think I'd posted this link:
http://www.etci.ie/news/harmonisedcablecorecolours.html
He's presumably seen the question, so maybe he'll now answer it.
As I read it, they seem to permit, rather than necessarily require it (my emphasis):
ETCI said:
They are indeed, including in the north where BS 7671 prevails. No-one in the north would ever consider using brown & blue T&E and oversleeving it - twin brown is always used, as was twin red before. Whether it is because people heard about the southern Wiring Rules and mistook it for an IEE Wiring Regulations requirement I cannot say.
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