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Topic Title: Harmonised conductor colours
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Created On: 29 July 2013 11:30 AM
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 29 July 2013 11:30 AM
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mrh105

Posts: 7
Joined: 25 July 2008

I'm working on a project to IEC standards and notice that the client has specified the power cable conductors to be red yellow and blue. When I raised the point that these are not the European harmonised colours, it turns out that IEC 60445 6.2.3 specifies that 'for line conductors in AC systems the preferred colours are black, brown and grey.' The consensus is that as the word used is 'preferred' black, brown and grey core colours are not mandatory.

My interpretation of the 17th Edition, is that identifying line conductors as black, brown and grey in a new 3-phase system is mandatory.
Has anybody come across this discrepancy between IEC and the 17th Edition before?
 29 July 2013 11:48 AM
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marclambert

Posts: 310
Joined: 23 June 2010

Not a discrepancy as such. Bear in mind that BS7671 is non statutory, therefore the word mandatory cannot apply. I'm told that in the power generation industry they had no intention of using the new colours in power station wiring, (though this may now have changed). I'm sure someone has more up to date info on the power sector, but the point is you don't have to follow BS7671 or IEC standards in the UK at least.
Regards
Marc
 29 July 2013 12:05 PM
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Avatar for OMS.
OMS

Posts: 19668
Joined: 23 March 2004

As above, BS 7671 isn't a "mandatory" document, but if you choose to deviate from 514.4.1 and 514.4.4, then the designers and other parties should be looking at 120.3 and the implication of the declaration on the EIC.

It could be argued under the CDM regs that using "old colours" is a safety issue (eventually, there won't be any old sparks about so it causes confusion) - but it could be managed by a client in terms of training and instruction - but that would rather depend on the building and its intended use.

I'm not sure I would be going RYB without a robust fight with the client and plenty of documented evidence as to why it was done.

It's quite possible that the client is just recycling a (Very) old specification

Regards

OMS

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Failure is always an option
 29 July 2013 12:50 PM
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mrh105

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Thanks guys, some interesting points.
The project is in the middle east, but IEC standards apply.
I was surprised to learn that IEC use the word 'preferred' when it comes to the conductor colours, where as the 17th edition does not seem to allow any deviation from the harmonised colours.
 29 July 2013 01:16 PM
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OMS

Posts: 19668
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OK, if it's Middle east then technically the Gulf Co-operation Council (GCC) and the wider Middle East, have no plans for change or have decided not to change their cable identification systems.

You often find cable in Group 1 (old colours) and Group 2 (new colours) offered for sale.

It's a bit of a problem as those countries will often specify IEC compliance - which as you've found out only suggests the new colours are adopted.

From experience, make sure what you do is well documented and then just crack on - if the cleint wants RYB then so be it.

We have actually managed to get that kind of thinking reversed however - dialogue with the client team or client representatives often makes progress when the benefits are highlighted (often it's just a cost thing - the more people using the new colours, the cheaper the cable gets - and it's availability is from wider manufacturing bases (which is where quality comes in)

Note BS 7671 is the UK wiring code - it's not fully harmonised with IEC and isn't always useful in the middle east anyway

Regards

OMS

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Failure is always an option
 29 July 2013 01:29 PM
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AJJewsbury

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it turns out that IEC 60445 6.2.3 specifies that 'for line conductors in AC systems the preferred colours are black, brown and grey.'

Does it say anything about N colours (or the use of blue)? (I get the feeling that common practice in some of our nearer continental neighbours was blue for N, G/Y for c.p.c. and anything else you liked for L (I suppose quite useful where even domestics are typically wired with singles in conduit and you want to be able to tell L from switch lines from strappers etc. - so I can see that there would be a reason for wanting the L colour to be a bit vague).) - I was just thinking that if blue is defined a bit more strongly than 'preferred' for N, then you wouldn't be able to use RYB and remain in compliance with the IEC.
- Andy.
 29 July 2013 03:25 PM
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cookers

Posts: 205
Joined: 10 February 2012

One of the certainties of life along with death and taxes is that colours of cable insulation change over time, also depends where you are, and they will continue to change.

I can remember Red as the "continental" earth insulation colour, but I am old and don't know as much as you younger types.
 30 July 2013 11:25 AM
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broadgage

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I have seen a picture of a job in the Middle East that used 4 core SWA in the old colours but with blue used for neutral, and red, yellow, and black as phases.
Nice compromise !
 30 July 2013 11:30 AM
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iie63674

Posts: 78
Joined: 17 May 2006

Andy, it does:
"Neutral or mid-point conductors
Where a circuit includes a neutral or mid-point conductor identified by colour, the colour used
for this purpose shall be blue. In order to avoid confusion with other colours it is
recommended to use an unsaturated colour blue, often called "light blue". Blue shall not be
used for identifying any other conductor where confusion is possible.
In the absence of a neutral or mid-point conductor within the whole wiring system, a conductor
identified by blue may be used for any other purposes, except as a protective conductor."
 30 July 2013 12:03 PM
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OMS

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Originally posted by: broadgage

I have seen a picture of a job in the Middle East that used 4 core SWA in the old colours but with blue used for neutral, and red, yellow, and black as phases.

Nice compromise !


I can vouch for that - we went through a whole exercise swapping them back at the contractors cost - although perhaps the clients fault really on his insistence on old colours and then doing nothing to quash the local rumours about de blacking the neutral resulting in the ad hoc adoption of blue neutrals in some building, black neutrals in others and absolutely anything goes in regard to phase colours and mainataining sequence.

It's the middle east after all - just shrug and crack on

Regards

OMS

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Failure is always an option
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