Replacing light - House that jack built!

[sparkwright]

I can't think of a single good reason why harmonised black should be used as the neutral. There's logic and even guidelines to use the grey, but nothing suggesting black.

Here are some examples of how the harmonised colours can get used for different applications.

3 core and earth for L, sw L, N
brown L
black sleeved brown sw L
grey sleeved blue N

SWA 3 core for L, N, E
brown L
black sleeved green and yellow E
grey sleeved blue N

SWA 3 core for 3 phase
brown L1
black L2
grey L3
armour E

SWA 4 core for 3 phase
brown L1
black L2
grey L3
blue sleeved green and yellow+armour E

SWA 4 core for 3 phase+neutral
brown L1
black L2
grey L3
blue N
armour E

Don't think any of these are interchangable, other than the 3 core+E at the top of the list.

Possibly people do the SWA 3 core for L, N and E differently, but again, grey as N for me.

 

[sparkwright]

Some more;
SWA 3 core for L, sw L, N
brown L
black sleeved brown sw L
grey sleeved blue N
armour E

SWA 4 core for L, sw L, N
brown L
black sleeved brown sw L
grey sleeved green and yellow+armour E
blue N

I can understand people may be uncomfortable about the two neutrals together on these two cables, but I think blue has to be the neutral if you got a blue there.

Another factor to discuss.

 

[JohnW2]

Don't think any of these are interchangable, other than the 3 core+E at the top of the list. ... Possibly people do the SWA 3 core for L, N and E differently, but again, grey as N for me.

Sure - with all the 3-phase ones, it would be ridiculous not to use brown/black/grey for L1/L2/L3, so leaving no scope for variants.

However, as per this whole discussion, in the two single-phase cases (3C+E or 3-core SWA), there is scope for disagreements about the use of grey and black. Like you, if a neutral is required, I would always use grey - but there are clearly at least some electricians who think differently.

In the final analysis, it's the sleeving that identifies the function of a conductor which isn't being used per its insulation colour - so, in that sense, it "does not matter", even though I would personally prefer to see a universal convention (only achievable if it were 'mandatory').

Kind Regards, John

 

[AndyPRK]

No wonder it took 24 years to adopt this for fixed wiring!

 

[sparkwright]

No wonder it took 24 years to adopt this for fixed wiring!

Not 34 then?

 

[AndyPRK]

Good point. Or 35 for that matter

 

[JohnW2]

No wonder it took 24 years to adopt this for fixed wiring!

In some senses, that 24-year 'overlap period' (if that's what it was - I thought it was a fair bit more than 24 years) was the most bizarre thing of all. Having decided on the change, it would surely have been more logical (and safer?) to implement the change for flexible cables and fixed wiring simultaneously?

One is tempted to think that this happened for 'commercial reasons' (so that appliances with the same flexible cables could be sold throughout Europe), despite the fact that the industry took a long time to accept (or 'give in to') to the colour changes for fixed wiring!

Kind Regards, John

 

[sparkwright]

I thought it was a good idea to do flex and the flexes on all appliances in harmonised colours, back in 1970 I believe it was.

However, I don't think it was a good idea to change to harmonised colours for fixed wiring in 2004.

All we ended up with was the mixture of colours, which 'spoilt' the design of older installations.

There is a potential danger of, for examples, major confusion of mixing up single cores in a trunking in a factory - the blacks and blues of a 3 phase and neutral system becoming something totally different.

Pointless changing the colours for fixed wiring. It's 'fixed', it won't be going anywhere else in Europe.

 

[AndyPRK]

According to Wikipedia (yes I know) it was because if safety concerns.

I.e getting the black and blue mixed up on 3 phase installations.

I would be nice if there was a sensible standard without having to always rely on sleeveing.

 

[sparkwright]

According to Wikipedia (yes I know) it was because if safety concerns.

I.e getting the black and blue mixed up on 3 phase installations.

I would be nice if there was a sensible standard without having to always rely on sleeveing.

I think there's more danger issues changing fixed wiring colours than appliance flex colours.

I don't think fixed wiring should effect the rest of Europe very much, so I think it was change for the sake of change.

With the unharmonised cables on fixed wiring, there seemed to be a sensible standard as you mention.

Though sleeving is very important, we do have to rely on it a lot, and also need to check a lot. If there was a standard we would still need to check, but would be proved right a lot!

 

[JohnW2]

However, I don't think it was a good idea to change to harmonised colours for fixed wiring in 2004. ... All we ended up with was the mixture of colours, which 'spoilt' the design of older installations. ... Pointless changing the colours for fixed wiring. It's 'fixed', it won't be going anywhere else in Europe.

That's a good point but, dare I say, I think it's the DIYers who were the greatest potential problem - for them, having that long period during which 'current' wiring colours were different for flexes and fixed wiring must have caused some confusion - and, I would imagine, inevitably some mistakes.

As far as the professions are concerned, I have a lot of sympathy with what you say.

Kind Regards, John

 

[JohnW2]

I would be nice if there was a sensible standard without having to always rely on sleeveing.

As I've said, I agree that a universal (probably 'mandatory') convention would be desirable. However, to do without sleeving would mean the need to manufacture, and for people to buy or 'carry', cables with quite a few variants of colour configurations.

Kind Regards, John

 

[AndyPRK]

The danger I was referring to was fixed wiring.
And it's a good point you mention about trunking

Flexable wiring colour change was sensible and understandable.

 

[sparkwright]

This is why I make such a fuss about using grey as the neutral on 3 core+E.

It supposed to be harmonised cable.

And we start making up our own colour choices, making the mixture of unharmonised and harmonised colours even deeper.

 

[AndyPRK]

I would be nice if there was a sensible standard without having to always rely on sleeveing.

As I've said, I agree that a universal (probably 'mandatory') convention would be desirable. However, to do without sleeving would mean the need to manufacture, and for people to buy or 'carry', cables with quite a few variants of colour configurations.

Kind Regards, John

I wasn't suggesting more cables with different colours.
Everyone understood the standard pre 2004.