ECN Forum Forums General Topics of the Trade Non-US Electrical Systems & Trades New U.K. color code

Paul,


I would tend to disagree with you. There is absolutely no reason for the UK, or any other country, to opt-out of harmonisation.

1) Economics:

For cable makers, equipment manufacturers etc etc. this standardisation opens up the entire EU (and Cenelec) market. The colour code variations are unnecessary barriers to entry. Small variations in mass-manufactured products can add a supprisingly large amount to costs.

Remember these regulations apply to 470 million people! (And tens of millions of others beyond the EU) the UK market represents a meer 57 million at most.

2) Safety.

With increased movement of people around Europe it makes a lot more sense that householders, professionals etc are always going to find familar colours when they open a box and try to do DIY work. The current system is a complete mess with some countries using colours for ground that others use for phases! I realise that it will take decades for the old systems to disappear, but, just like round-pin-plugs in the UK, they will eventually be banished to history.

In domestic cabling systems I don't think it's at all acceptable to expect householders to deal with 2 different colour codes. Many younger people would be completely baffled by Red/Black and Green cables behind a socket, yet might attempt to wire it anyway.. Consumers are very familar with the harmonised flexible wiring code.

These are the kind of differences that make economies of scale in the EU much more difficult to achieve than in the US. If Europe's to actually become more economically dynamic it has to harmonise and remove some of these internal and utterly unnecessary barriers.

Interestingly I've noticed that ESB in Ireland uses the harmonnised colours on the cores in heavy LV distribution cable.

Valid points there, but I'm not sure I can agree with them fully.

1. Economics. As one of the articles linked to on the IEE page points out, the most commonly used styles of British cable, such as our "twin & earth," aren't widely used elsewhere in Europe. That being the case, there seems little to be gained, unless we're going to adopt Continental-style cables along with the new colors. (By the way, that link says that our SWA-type cable isn't very common on the Continent -- Can anyone confirm this?)

2. Safety. I can see an argument for common coding of appliance flexes. Appliances can be sold all over Europe, moved around easily, and as we still have varying types of connectors at least in the U.K., Ireland, Denmark, etc. people will need to change the plugs.

I don't see that the same requirement applies in any way to the fixed wiring in a building. People don't take building electrical systems with them when moving to another country (well, most people don't ).

I wouldn't be too sure about younger DIYers not understanding the old red/black coding either. Even though the brown/blue systemn has been used on flex for over 30 years, anyone who has ever opened up a wall socket will have seen red/black, no matter whether it was installed a week ago or back in 1930.

Trumpy,
The official documentation here does actually use "harmonisation." I'm just used to writing harmonize, recognize, realize, etc. so I use those spellings automatically unless specifically referring to a different spelling.

Off-topic English lesson : The -ize form is actually the original spelling of these words, hence their dominance in America. The British -ise endings are a relatively modern variant, not in widepsread use until quite a way into the 20th century. My old "King's English" dictionary from the early 1930s lists only the -ize forms as standard in the main text, with -ise noted as an acceptable variant in the addendum.

When it comes to underground cables, it seems that the British SWA and the German NYYJ are de facto standard in many countries outside Europe. (Not including North and South America)

Europeans seem to prefer the round NYM cable to the flat T&E. Both are common around the world, but may carry some local designation. Clever marketing trick: The manufacturers sell the same cable in several countries but with different names and approvals to confuse the buyers and keep competition down. The British T&E can't be used in countries where a full size earth is required.

Below is a link to the documentation for an Israeli cable: The document refers to British Standard, VDE, Israeli Standard and IEC standards. (Note: Slow server)
http://www.cvalim.co.il/products/catalogue/PCD45-3.pdf http://www.cvalim.co.il/products/catalogue/PCD45-3.pdf

Is there any real safety advantage of a full sized earth over Twin & earth UK style cable?

In most instances once there's a path to earth at all it will trip an RCD pretty much instantaniously.

I can see it being more of an issue where fuses were the sole means of protection as it was more likely that an earth/ground cable would need to survive a high current until the fuse blows.

---

I realise that a larger earth cable would potentially reduce impedence etc.. but is it actually that vital?



[This message has been edited by djk (edited 04-06-2004).]

The larger earth conductor would reduce the "touch" potential at the point of the fault compared to the reduced size, although as you said, that's really only likely to be an issue on a non-RCD circuit with allowable disconnect time of 5 seconds. (By the way, do the Irish rules have similar 0.4 and 5 second requirements?)

I know that American NM cable (Romex) used to have a reduced-size ground wire. I'm not sure when it was made full size or what the rationale behind the change was.

By the way, according to the IEE the new cables will be available from stockists "On or soon after" March 31.

I haven't found anywhere around here stocking them yet. How about our other U.K. members?

I asked in City Electrical Factors if they had the new cable in yet but they only had the old type.

I plan to start using the new cable colours on all new builds when it is available and use the old coloured cable on existing installations to avoid having to remark the old cables when they are mixed with new, will be ok until the old cable colours are phased out.

I wonder how long it will take the supply providers to remark the incoming cable and meter tails on old installations?

Paul, Ever-ready,
Our 4mm and 6mm 2C+E and 3C+E TPS uses the 2.5mm Earth Conductor.
The thing about an Earthing Conductor, is it only carries current under Fault conditions, there-fore, it is Down-sized.
Biggest thing with any sort of Earthing system is your connections.
An effective Earth is only as good as the terminals that Bond it, to the said Earthing Point.

I went to buy T&E cable from my local branch of Wm Wilson (the cheapest for cable at present)on Thursday, and was unable to get any 1.0mm 6242Y (old or new colours). There was 1.5 & 2.5 T&E & 1.0 & 1.5 3c&e available in the new colours.

I was surprised to see the "harmonized" stocks (manufactured by AEI cables) come in so quickly, however I was specifically looking for cable with the existing code to complete a job already started.
I was told they had about 8500M of 1.5 & 2.5 T&E available in the "old" colours and when that was sold only the new colours would be available.
There was also 25mm 6181YH (meter tails) with a blue core / grey sheath available, but not the corresponding brown / grey cable. The blue / grey cable did look strange, but I guess we'll get used to it soon.

If this is any indication it looks like the conversion process is going to be fairly quick in the T&E type, house wiring cables.

As I've said before I would much prefer to keep our existing code, but I do see that we are somewhat isolated in using black as neutral and the change was inevitable. In single phase installations this should be fairly straight forward and safe, but 3 phase installations may be more of a problem.
Incidentally, I have had a few customers comment that their wiring must be really old because it is red, black. They are then surprised when they see me install cables with red & black cores, though not for much longer.


[This message has been edited by David UK (edited 04-10-2004).]

BDC-Bridisco (my usual supplier) don't have any of the new cables in stock yet, although with the copper price fluctuations at the moment I guess we should be thankful for any cable we can get.

One thing I have found with BDC is that they seem to run out of quite common items all too regularly these days. The Norwich outlet, despite being listed as one of their "Super-warehouses" often has no stocks of 4mm 6242Y.

It will be interesting to keep an eye on B&Q, Homebase, and the other DIY chains to see when they first get the new cables in too.

Going back to the new colors, I've never been happy with the adoption of blue for neutral on flexes. It makes no sense to me.

I accept that Britain was (and still is) somewhat isolated in the use of black as a neutral when almost everywhere else in the world (outside of British influence) uses it as a phase.

But I think a better choice could have been made 30+ years ago when the new standard was being drawn up. What would have been wrong with adopting gray as a neutral?

Gray was already in use as such in Germanic countries, not used for anything in British territories, and it would have had the additional benefit of at least partial "harmonization" with North American standards if the true aim was to minimize worldwide difference in color coding.



[This message has been edited by pauluk (edited 04-11-2004).]