It's several weeks since I posted in another thread that my usual supplier was finally carrying the new harmonized cables. Judging by the comments from others, I think this must have been about the last area of the country to see them!

It appears that resistance is futile (except in Ohm's Law ) and today I had to come back from the supply house with my first ever purchase of cable in the new colors (a reel of 3-core 1.5mm SWA).

The new colors pose a query in situations where a 3-core armored cable is to be used for a single-phase feed with one conductor acting as a supplemental earth to the armor.

With the traditional 3-core red/yellow/blue, I always applied black tape or sleeving to the blue for use as the neutral, and green/yellow ID to the yellow for the earth. I wouldn't mind betting that's the way most of us in the U.K. did it.

But have any of you adopted a preferred convention for the new cables?

Assuming brown is left as-is for the single phase line, which way round would you re-identify the remaining conductors for use a neutral and earth?

1. Black -> Blue; Gray -> Green/yellow;

or

2. Black -> Green/yellow; Gray -> Blue.

I don't quite follow. Why would you use a 3-phase cable for single phase? Are you allowed to turn any conductor into PE and N?

Well, when terminating in an insulated enclosure it's often easier to run a 3-c rather than t*t about trying to make a bonding terminal using/secured to the armour tag and thus make yet another hole in - say - a weatherproof enclosure. And theoretically you could use any conductor for any purpose if sleeved accordingly ( or taped ), but the designation Paul states in his post was the 'norm'



It would appear that the grey is used as the PE when sleeved G/Y Paul - or so I'm told This leaves the black as the neutral which is "easy" to remember!! The 'official' changes are: red>brown, yellow>black, blue>grey. Hmm...officialdom...

The 3-core SWA I have on stock has all three brown - you you pays yer money and takes yer choice! I also have 3 browns and a blue ( 4-c) which is a !"£$%^&* nightmare when the clown you have assisting you doesn't clip the ruddy numbers on properly in a nice big enclosure with multiple entries!! Oh well...another adage - "You get what you pay for" !!!!!


[This message has been edited by uksparky (edited 11-05-2004).]

The Irish rules are a little more limiting:

(quote from the ETCI (ElectroTechnical Council of Ireland)

The following limitations apply:

1) Green/yellow cores shall be used only as protective conductors and shall not be converted e.g. by sleeving for use as neutral or line/phase conductors.
2) Blue cores shall be used only as neutral conductors and shall not be converted e.g. by sleeving for use as protective conductors or line/phase conductors.
3) Brown, black or grey cores shall be used only as line/ phase conductors, and shall not be converted e.g. by sleeving for use either as protective conductors or as neutral conductors.
4) 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.
5) For single-core cables used for three-phase circuits, the core colours shall be the same as for multi-core cables.
6) Where single-core cables are used to supply single-phase circuits fed from a three-phase distribution board, the respective line/phase conductor colour may be extended to the single-phase circuits fed from that phase.
7) Sleeving or tape used for identification purposes shall be permanent, heat resistant, colour-fast, non-conductive, and shall comply with EN 60454 or other appropriate standard.
8) Four-core cable without a blue core e.g. NYM-J shall be used only for circuits with balanced three-phase loads e.g. three-phase motors.


(Also the phase order is Brown (L1) Black (L2) Grey (L3)) Single phase systems, just like flexible single phase cables on appliences, use Brown as the live.

Armored cable aside, there are also times when we need to re-identify the cores of regular 6243Y 3-core cable as well. (That's the 3-core plus earth version of our common "Twin & earth" style cable.)



If using this to feed a timed bathroom fan, for example, you would need the red and yellow to provide permanent-live and switched feeds, with the blue tagged black to become the neutral.

Ah yes, the R/Y/Bu phases have become Bn/Bk/Gy, so if we adopted a straight substitution I guess that would leave black to be re-identified as earth and gray to be taped/sleeved blue for neutral.

I'm not sure which scheme I like the sound of yet!

Reading that list it seems as though the only permitted change of colors is to re-identify from one phase to another.




[This message has been edited by pauluk (edited 11-06-2004).]

Well actually you would need the brown and black to provide permanent-live and switched feeds, with the grey tagged blue to become the neutral on a straight substitution! Just how excruciating is that!?!

I forsee many splinters as sparkies scratch their heads for years to come...

Paul, it occurs to me; how has your supplier got around the supplying of products that should not have been available after the 31st March?



[This message has been edited by uksparky (edited 11-07-2004).]

There's nothing to get around. According to the Regs. the new colors have been permissible since March 2004, but cables to our traditional colors can still be installed until March 2006.

Despite the rest of the mess of the changeover, at least the IEE had the sense to allow a 2-year changeover period.

I don't think there will be anything to stop anyone from selling cables to the old standard after March 2006, if they happen to still have any in stock.

According to the Autumn 2004 issue of NICEIC Connections, the method to be adopted should be Brown - phase, Black - PE and Grey - neutral.

The reasoning behind this is to try and stop the association of black being a colour associated with the neutral. They recommend in all circumstances black should never be used for a neutral connection.

Ian

I suppose that as black will now be phase B they might have something there, but considering the millions of installations in which black (without re-identification) is already a neutral is does seem a moot point.

Uhuh...sorry Paul you're quite right! I must confess to not reading the bumph too closely and just accepting the change. However, on the flier we received from our supplier we were not able to obtain 'old' cables after 31/03/04 "as [they] are no longer permitted to sell them".

What a mess...

Yep, that just goes to show how much misinformation is floating around out there.

I still think this is one area where we should have put our foot down and just said "No, we will not be changing."

This change has far more to do with politics than with any genuine technical reason.

In Austria the book says this: Blue is only to be used as a neutral and all neutrals have to be blue. y/g is ground only. Only exception to the rule: grey (as in NYM-J 4x1,5) can be sleeved blue as a neutral. After the changes suppliers ran out of blue heatshrink tube.
Phases can be about any color except blue, y-g, yellow and green (not sure about the two latter, might be just Germany). The Germans just switched back to grey neutrals when using such cable

What I can't figure out is why blue came to be adopted as neutral in the first place.

It was clearly already established standard in some European countries by the 1960s, but does anyone know exactly where and when the use of blue neutrals originated?

If we had to change colors to a common standard, wouldn't gray have been a better choice anyway? Germanic countries were already used to gray being neutral and it wouldn't have clashed with existing British usage of blue as a phase. Were any other countries using gray as anything but a neutral 30-40 years ago?

Would have to dig up the age old thread about the old color codes, but I think there were definitely some countries that used grey as a phase.
All countries around here used dark blue as a phase too! Depending on whether it was a four- or five-wire system you had: black, red blue or black blue black for the phases. Possible combinations were: 4 wire TN-C: L1 black, L2 red, L3 blue, PEN grey. 4wire TT/TN-S: L1 black, L2 blue, L3 black, PE red. 5wire: like 4wire TT/TN-S but with a grey neutral.

The problem with the old color coding was the fact that the colors weren't sepcific. Red could be ground, PEN and phase, grey could be N or PEN, black could be about everything. With three or four way switches every color could become about anything. If conduit was used people didn't care at all as long as PEs if existant were red, but not even that was always the case (seen black and brown ones too in Germany).

Paul,
As I was always taught, the use of a Blue Neutral, came from the flex colouring.
In that, people with colour-blindness are less likely to get the Brown-Blue colours mixed up, as opposed to the old Red-Black.
People that are colour-blind usually cannot distinguish between Red and Black for same reason.
This colouring started with flexes because of consumers transposing the P-N wires on appliance plugs.
Just as a note, this colour coding thing sounds like a right nightmare.
People,(especially Electricians) will have to be doubly vigilant when working on electrical systems in a few years down the track.
With regard to sleeving wires, I don't personally like the idea of doing this, but then again, in existing installations, there is usually little choice, the thing that worries me the most when working on domestic systems, is where wires are sleeved in the middle of a run, 1 circuit I worked on a few years back, had 3 different coding changes along it's length, where new bits had been added over the years.

The colour blind problem is between red and green which under the old 'British' system was potentially fatal.

Doesn't explain where the blue came from though - maybe for a colour-blind person it makes it the most discrimiating trio of wires?

I too was always led to beleive that the inability to distinguish between red and green was the most common form of color blindness.

Obviously with red as phase and green as earth a transposition could be disastrous, but I've often wondered whether this has been over-emphasized. Maybe I've misinterpreted something, but I was under the impression that people suffering from red-green color blindness saw the two colors as being the same. If that's the case, then surely they wouldn't just guess at which is which?

If we're talking about electricians here probably not, but DIYers _would_! Most definitely!