Simple phase colour question

[Mattenstein]

Hi all

I'd just like to know out of interest, in these days after harmonised core colours in cables e.g. where a 3 core & cpc cable changed from red/blue/yellow to brown/grey/black, how does the DNO identify the 3 phrases? I believe they were originally red/blue/yellow too, are they now known by different colours?

What brought me to ask is that certain areas of my town had a power cut tonight and it reminded me of the time my terraced house and the two adjacent had no power but the rest of the terrace were unaffected, am I right in thinking it was the particular phase we were on that had tripped out at the substation?

Cheers

Matt

 

[AndyPRK]

Yes and yes.

Neutral being blue now.

 

[Iggifer]

Blue if they even bother to mark the neutral.

In PME/CNE heads they don't bother doing anything with the bare strands - which I assume is standard practice for them. Haven't seen an SNE install being done for a long time

 

[Mattenstein]

Cheers

I know Neutral is now blue; my house was rewired in 2014 and one of few things they left and reconnected was an outside PIR light I'd installed (must have done something right). I was under the impression that all the live wiring in my house would now be brown/blue and any red/black would be dead, but a few months ago the aforementioned light conked (PIR no longer functioning) so I set about replacing it, was surprised to find the cable I'd used was r/b and hadn't been ripped out....anyhoo I'm happy to leave it there!

Another think that struck me is that every wire in a light switch, except neutrals where they exist, has to be brown or sleeved brown.....Made my life hard replacing a 2G-2way switch in my hallway! I appreciate the reasoning but wouldn't it be sufficient just telling people that every core is potentially live? Or perhaps there's a H&S/insurance reasoning behind it?

 

[EFLImpudence]

I appreciate the reasoning but wouldn't it be sufficient just telling people that every core is potentially live? Or perhaps there's a H&S/insurance reasoning behind it?

The regulations merely state that conductors must be identified.
You can do this with the accepted colours or alpha-numeric notation.

I agree with you that where all conductors are line - neutral is considered a live conductor - and connected to switches and no neutrals are present or even all in a separate connector, it is hardly necessary to sleeve them all brown, being identified by their position.

 

[ban-all-sheds]

Another think that struck me is that every wire in a light switch, except neutrals where they exist, has to be brown or sleeved brown

No - cpcs must not be sleeved brown.

Made my life hard replacing a 2G-2way switch in my hallway!

How on earth did it do that?

I appreciate the reasoning but wouldn't it be sufficient just telling people that every core is potentially live?

Anybody who is rightfully fiddling with the wiring of a switch would already know that.

 

[Mattenstein]

Thanks everyone.

I am intrigued by this initiative to educate people that a phase conductor is 'line' but can't be called 'live' because neutral is a 'live' conductor also. Yes neutral carries current, I am aware of that, but isn't this measure akin to sleeving every conductor in a light switch brown? Aren't they both kind of measures of insurance against people who really really don't know what they're doing?

 

[Mattenstein]

No - cpcs must not be sleeved brown.




How on earth did it do that?



Anybody who is rightfully fiddling with the wiring of a switch would already know that.

I've been admiring your posts a while BAS, you strike me as the electrician's equivalent of the Grammar Nazi....
I am well aware of what to do with CPCs, I did replace a plastic light switch with a metal dimmer....moved the existing CPC to the terminal on the switch, sleeved a piece of 1mm and connected it between the switch and back box.
As for the switch in my hallway, 2 sets of red/blue/yellow or even 2 sets of brown/black/grey would be easier to cope with than 6 bloody brown conductors in my view! I did my best to remember what went where and did bugger it up once but I know how 2-way lighting works and knew what I had probably done wrong so I got there in the end

 

[EFLImpudence]

I am intrigued by this initiative to educate people that a phase conductor is 'line' but can't be called 'live' because neutral is a 'live' conductor also.

It's just semantics. We don't call them 'phase' any more.

Yes neutral carries current, I am aware of that, but isn't this measure akin to sleeving every conductor in a light switch brown?

Not sure what that means. I said I consider conductors connected to a switch are identified by that.
Some switches have a separate terminal for 'parking' neutrals.

Aren't they both kind of measures of insurance against people who really really don't know what they're doing?

No. It doesn't help people who don't know what they are doing.
Some people don't know what a switch does.

 

[flameport]

Live conductors are those which carry current in normal operation. Line and neutral are both live conductors.
Wires at a light switch are sleeved brown because they are both line, light switches do not generally have neutral connections.
If using T&E cables the proper way is to use cable with two brown conductors inside, however it is common to use brown/blue with the blue oversleeved brown as that avoids having to buy a separate roll of brown/brown.

For a simple light switch in a house it is usually obvious they are all line. However there are other situations where it may not be as obvious, such as a gridswitch panel containing 24 modules of various types connected to multiple phases, some modules with neutrals and others without. As it would be desirable to have the wires properly identified there, so they must be identified in other places as well - you can't have multiple rules depending on how complex/simple the circuit or panel is.

As for the colours, they were red/white/blue before the yellow arrived. DNOs and the electricity boards before them used various identification methods including other colours, numbers, letters and various combinations of all of those.

 

[winston1]

In my opinion switched wires should be identified with another colour. In Australia they were white in red/black days, not sure what they do now. In France switched wires are mauve or orange, or both used in two way switching systems.

It would mean having special cable with brown and orange or all three but so what?

 

[securespark]

Was green a phase colour once?

My 13th Ed. has the three phases listed as R, Y and B but Phase Y is listed as being white.

 

[winston1]

I have an iron in the loft from the '30s with brown for the earth wire, so maybe green was a phase colour then.

 

[JohnW2]

Was green a phase colour once?

Historic remnants next to the DNO fuses for my supply suggest that the answer is 'yes' (The 'A', 'B' & 'C' phase identifiers on the cables which enter the meter are also rather novel!) ... (and I've commented previously on the red insulation of the incoming neutral - which they've now hidden with some grey silicone!) ...

Kind Regards, John

 

[Mattenstein]

I've established that brown/grey/black are the colours used to identify the 3 phrases now, as they are the colours used in 3 core cabling. OK Then.

For anyone interested about my 2g-2way light switch change, my lighting has been wired with looped singles, so the line is looped at the switch and the neutral at the ceiling rose. This didn't affect me changing that switch though, it was the sea of bloody brown wires (ha, racist much?)
I did try remember which conductor went where when I removed the old switch, but the fact that all 6 bloody conductors were brown made it a bit difficult and I did mix a strapper up with a perm live, for instance!