ECN Forum Forums General Topics of the Trade Non-US Electrical Systems & Trades Yellow?

They're a bit tight but those are the rules.

According to all codes I know, Yellow-green must not be reidentified any other color (except for PEN conductors getting a small blue tag at each end) and no other color may be reidentified yellow-green. Period. Blue can be a phase if there is no neutral present, if there is a neutral it has to be blue and the only blue conductor.

Given the mish-mash of schemes we now have in operation, plus the confusion surrounding the changeover to the new system here which has already led to cross-connections, I think the only safe approach now is to assume that any color might have been used for any purpose.

By the way, does anybody know which was the first country to adopt blue (*) as a national standard for neutral? Was it even in use as such before the pan-European standards committees decided to go with it?

(*) Light blue officially, a point which some cable manufacturers seem to have forgotten.


[This message has been edited by pauluk (edited 12-15-2005).]

Pauluk, I'd also like to know which country started the green/yellow earth caze ? Isn't it just easier to have a green earth colour ?

The blue neutral hasn't been adopted in Australia / New Zealand yet ( except for imported appliance cords )

Paul,
I agree mate, it's become a real disaster as far as management goes, considering that we have a whole range of systems of identification, none of them really co-ordinated, it's just a good thing that people like ourselves know to be able to trace circuits and know what the colours could mean.
We haven't been hit here by the new colours here yet, but you can bet it's in the pipe-line.
Kiwi,
I have an idea that the Green/Yellow Earth wire started in the UK.
(If I'm wrong, no doubt I'll be corrected)
Reason I say that is because appliances in the UK were/are sold without a plug fitted.
Red/Green and Red/Black colour blindness is the most common.

I was always under the impression that green/yellow was adopted into the U.K. regs. originally because it was already in use in Continental Europe, so I don't think it was us. It started out here as just a permissible alternative to the standard plain green.

The original 13th edition IEE Regs. specify only green. The earliest reference I can find to green/yellow is in my ASEE guide which is for the 13th edition as amended to December 1963:


Note that this permits green/yellow for flex only, not for fixed wiring.

This is carried on into the 14th edition of the Regs in 1966. Table B.4, specifies green as the only acceptable color for fixed cables, but under the column for flex states:


As I understand it, several Continental countries had already adopted green/yellow exclusively for earth by this time, throughout their systems.

To continue, the 1970 amendments to the 14th edition introduced European colors for appliance cords here with their blue neutrals, and provided for the phasing out of the traditional system. Table B.4 is amended accordingly. It's easier to reproduce the table than to try to explain:



In case the note referenced by the dagger is illegible on your monitor, it says:


That last part is worth comparing with the 1963 quote above which clearly permits green/yellow to be used in conjunction with red and black.

Although red, black, green -OR- brown. blue. green/yellow in later years were the norm, I have actually come across one or two cords which did have red. black, green/yellow, although they're pretty rare.

Note that the 1970 amendments now also permitted green/yellow for earth on fixed wiring as well, although in my experience most installations from the early 1970s still just used plain green.

By the 15th edition 1981, plain green had been removed as an acceptable earth color entirely. I don't have the appropriate amendment to hand, but I believe that it was an amendment sometime around 1977 which then mandated green/yellow for fixed wiring as well.

And that is how it then remained until the latest round of changes from 2004 onward.


So to summarize the U.K. changes::

1963 Green/yellow permitted as an alternative in flex only (green still preferred)

1970 Green/yellow permitted as an laternative to green in fixed wiring. Flex may now be traditional red. black, green, or European brown, blue, green/yellow.

1971 All flex must now be European brown. blue, green/yellow.

~1977 Plain green no longer permitted for fixed wiring.

2004 Brown and blue permitted as alternative to red and black for fixed wiring.

2006 All fixed wiring to use European colors.



[This message has been edited by pauluk (edited 12-18-2005).]

When the colours changed for flexible cords here in the late 70's the earth conductor was still solid green in the 3 core flex I was using, even though live and neutral were now brown and blue. I seem to remember it remained thus for a few years.

Austria and Germany didn't change from red ground to yellow/green until at least 1967, Austria maybe even later. I think yellow/green was chosen because it has never been used for anything else before. The only other striped conductor I've ever heard of is the old Swiss red/yellow ground, which changed to yellow/green pretty early (I think 1950ies or early 60ies).
Until today black/grey/red cables are found not that seldom here, but we don't even learn the old colors at school any more. At least tow class mates asked me whether I had any idea what the red and grey wires at home could be...