3 Core And Earth Colours

[RandomGrinch]

I did once buy a roll of 12 core but never 20 core!

I've never had to buy 20 core, but then I do have a large stash of Centronics cables!

 

[JohnW2]

Genuine questions: Is there a reason for this lay-out?
View attachment 312635
In a single phase system, would it not be 'better' electrically if the neutral were where the black is instead of at the edge?

If you're thinking of the one possible 'advantage' of having a bare CPC that I mentioned, I suppose it doesn't make all that much difference. From that POV, the important thing is that, with either of those arrangements (i.e. 'as is', or with black and CPC swapped) the CPC is between the N and L(s).

I suppose one could just about argue that it would be 'better' if the P/L (as opposed to the S/L, if that's what the black was being used as) were adjacent to the CPC, but I think the relevance of the difference is probably pretty marginal.

Kind Regards, John

 

[JohnW2]

At the risk of repeating myself here is my take on it.

It was, for a number of years Red/Yellow/Blue representing the three phases (or Lines if you like) and Black was N. Actually before that it was Red/White/Blue too.

Indeed. In fact nearly all of the 3C+E I inherited in my house was Red/White/Blue.

A common trick, especially after the event of European harmonisation of flexes, was to use Red as L, Yellow as SL and Blue as N . Red being commonly L and Blue being commonly a N colour of flexes. The Yellow should have been sleeved Red really (but often was not) and of course the Blue should have been sleeved Black but very rarely was in reality.

Yep, I think that's what most of us did.

So, although we were told for years that fixed wiring colours "Will never change, only flexes have changed for Europe", we did all change to the horrible Brown/ Black/Grey. ... One thinking was that if RYB became Br Bk Gy then R now Br, Y now Bk, Blu now Grey. .. .. That also dissociated Black from N. ... So, we end up with Brown = L, Black (now sleeved Brown) = Sw L and Grey (now sleeved Blue) = N. .... Well that`s what I think how it became/should have become what it is today.

That's certainly a logical and fairly credible possible explanation.

I do not like those "New Fangled, Killer Colours" that we have today.

I definitely agree, and not just because of my memories of past systems/conventions.

I have no problem with blue for neutral (actually 'feels' fairly reasonable), nor with G/.Y (or green) for the CPC. However, even if we were starting from scratch (i.e. with no 'prior conventions' to bias us) I personally think that (for fairly obviously reasons) brown feels intuitively like 'earth'. Red, on the other hand, is very widely regarded as a 'danger' colour, and therefore seems appropriate for the L.

Kind Regards, John

 

[SUNRAY]

Surely it doesn't matter with 3p.

I'll not bother replying to that

Genuine questions:

Is there a reason for this lay-out?
View attachment 312635

Yes of course there is, the live conductors are are arranged in ph1, ph2,ph3 order.

In a single phase system, would it not be 'better' electrically if the neutral were where the black is instead of at the edge?

Why? Are you meaning should we have used the yellow for neutral in previous colour scheme?

Perhaps you could share your enlightening moment.

I did, have you not read what you are referring to?

I assume the remainder of this is now clear after noticing the colour order I suggested.

Did they not do that? Edit - just realised you mean instead of Brown, Black, Grey.


I do not understand.

On the one hand, they did not do that. How could they?
On the other hand, they did not do the alternative either; hence the requirement (in sp) for brown or blue sleeving on black and grey wires.

 

[JohnW2]

Why? Are you meaning should we have used the yellow for neutral in previous colour scheme?[

As I recently wrote, I assume (maybe wrongly) that EFLI was talking about what I had said about the one arguable electrical advantage of having a bare CPC (and one positioned between L & N) - namely that it increased the probability that something penetrating or damaging the L or N conductor would also come in contact with the CPC, hence causing a protective device to operate.

I would guess that EFLI felt that such would be more strongly the case if the CPC were adjacent to the P/L (and N) rather than the S/L (and N) (when that's what the conductors were being used as) - but, as I said, I'm not convinced that there is a lot of difference.

Kind Regards, John

 

[ebee]

View attachment 312638
Data from Elandcables

Thanks for that Bernard.

The signal cables I was reffering to was the traditional 4 core for alarm cables then 6 core then 8 core then 12 core then eeekkk! 20 core.
They were all single colour.
I you start at 4 core they were the standard traditional three phase plus N colours the add two for 6 core (Green and White) then add two more for 8 core (Brn and Orange) etc etc.
If I remember rightly, one of them had two blues, a dark blue and a light blue. Might have been the 12 core but not sure now. I used to know all the colours but these days after 8 core I`m mentally challenged these days.
Like I said, I did a few with 12 core but I don`t think I ever used 20 core. 4, 6 and 8 were plenty for most jobs. 7 stranded semi-flexible.
This was in the days when intruder alarms were basically two loops plus, if a PIR detector etc, then +ve and -ve.
BT cable was single core and then body colour plus a band colour. Although some used BT cable for burglar alarms too.
Nowadays you might well use power plus one loop for both alarm and tamper signals. Or an "ID Biscuit" but now very common computer data cable (CAT 6 etc) on a bus for everything.
Or (dare I mention) Wireless?

 

[ebee]

One loop of bellwire , a lever-microswitch on the door and a friedland bell , anyone?

 

[JohnW2]

One loop of bellwire , a lever-microswitch on the door and a friedland bell , anyone?

'Once upon a time', yes - later evolving to include more lever microswitches and some magnet/reed switch ones - and finally, when technology allowed it, some IR LED/photodiode detectors and, eventually, PIRS

Kind Regards, John

 

[ebee]

IR Photo beams and them dark glasses like in the 60s Films .
Mind you back then it was "Ok cut the mains power to the property so the alarm will not work!" Oh yeah???? LOL

Mind you, all the top burgling gangs had a thermic lance and did neat job of getting into the bank vault in the basement by cutting thru from next door. Spent all weekend doing a nice tidy job.
Today the put a gun to the keyholders head and say "Let us in!"

 

[DetlefSchmitz]

some IR LED/photodiode detectors and, eventually, PIRS

...so that people with cats couldn't have one...

 

[JohnW2]

...so that people with cats couldn't have one...

Which? I presume you mean the PIRs? The "IR LED/photodiode detectors" would rarely, if ever, be triggered by cats if their beams were high enough up to be very unlikley to be broken by cats, even jumping ones

Kind Regards, John

 

[DetlefSchmitz]

You haven't seen our cat catching flies!

 

[SUNRAY]

As I recently wrote, I assume (maybe wrongly) that EFLI was talking about what I had said about the one arguable electrical advantage of having a bare CPC (and one positioned between L & N) - namely that it increased the probability that something penetrating or damaging the L or N conductor would also come in contact with the CPC, hence causing a protective device to operate.

Kind Regards, John

I interpreted this:

View attachment 312635

In a single phase system, would it not be 'better' electrically if the neutral were where the black is instead of at the edge?

a different way.

 

[sparkwright]

People who use black as the neutral on a harmonised 3 core+E should be lined up against a wall and shot.

 

[EFLImpudence]

Bang. Bang.

I see what the reasoning is:

It is that 3p used to be R,Y,B for L1,L2,L3 respectively and when the cable was used for 1p the Blue was quite naturally used for Neutral. Then harmonised flex came along with a Blue neutral so all was well and obvious.

However, when harmonised 3core&E; Bn,Bk,Gy; arrived, and when used for 1p, you, and others, for some reason decided that '3p L3' must therefore be used for Neutral even though most properties would still have been cabled in Red and Black with Black as Neutral.

Of course, any instruction to this effect; that Grey should/shall be used for Neutral; is irrelevant and impossible because Grey is not a colour that signifies Neutral so must be over-sleeved or marked for identification; exactly the same as a Black wire - the base colour being immaterial.