Curious on Mains flex colours

[neon indicator]

The Wikipedia only lists when Brown and Blue came in for fixed mains wiring. (2004 to 2006 apparently in UK, doesn't say Ireland).

But while the BS1362 or whatever the rectangular pins rather than 4 types of round pins came in maybe 1947 and started to be common in 1970s, when did flexes first have Brown & Blue instead of Red and Black in the appliance plug/flex?

[Lucien Nunes]

AFAIK the CENELEC agreement that instigated the change in UK flex colours was 1970, but the wiring regs permitted red / black / green until April 1971.

Incidentally BS1362 is for the 1-inch cartridge fuse, BS1363 is the 13A plug.

Lucien

[teetoon]

This has been covered in a previous thread but, my memory says 1969. I was in my last year at primary school and got involved in helping out at a temporary site for the local British Legion Club. I used to help the electrician (passing tools up the ladder, fetching things etc) and I often went to the wholesalers to get supplies. On the wall was a big poster showing a piece of circular flex with the new colours. I remember asking if it was a special cable and all was explained to me. Next year 1970 our local electricity board showroom (SWEB) had a stack of reels inside the door of old coloured rubber flex at 4p per metre and I bought some for making extension leads. Still have a short length of the 2 core, good quality with string fillers.

David.

[broadgage]

I believe that yellow/green was permitted for earth before phase and neutral had to be brown and blue.
I have found old flex with green/yellow, red and black cores.

I have found fixed wiring with black earth wires, permited I believe in the 1930s, though I stand to be corrected on this.

[neon indicator]

I lived in UK till 1983, so I have no idea when Ireland introduced the "new" colours either.

[paulsherwin]

I think all European countries changed over in the first half of the 70s. We are stuck with the rather odd blue/brown colours because some countries actually used red for earth, so red couldn't be used in the standardised system.

[neon indicator]

UK post office BT used red for earth too
But logical as the supply volts was -48 (really -42v to -55v approx)

The US used Black for live and white Neutral. Likely still do.

[brenellic2000]

The first full-page colour adverts of the new colours were certainly appearing in very late 1969.

It worries me that so many are reliant on 'Wikipedia' for their research! With the greatest of respect and very long experience, that's the last place you should turn to as a source for authoritative information!

Barry

[broadgage]

Originally Posted by neon indicator

UK post office BT used red for earth too
But logical as the supply volts was -48 (really -42v to -55v approx)

The US used Black for live and white Neutral. Likely still do.

They still do, in fact live can be almost any colour except white, grey, green, or green/yellow.
In practice though black is normally used on 2 wire circuits.
Twin and earth cable comes as standard with black and white cores, with a bare earth.
3 core flex normally has black, white and green cores.

Neutral can be white or grey, by convention white is used on systems operating at 120/240 and 120/208, whilst grey is conventionaly used on 277/480 volt systems.

I believe that the harmonised European colours were intended to be light blue for neutral and dark brown for live. The idea being firstly that colour blind persons would know that dark wire=live and light wire=neutral and that the striped one is the earth. Also in monchrome illustrations it would resemble the USA code refered to above.

These days any shade of blue and brown seems to be used.

[Station X]

Post Office Telephones and BT never used red for mains earth. Low voltage DC supplies used red for positive (earth) and blue for negative (battery).

[Reelman]

Am I right in thinking that flex changed to the new colours long before twin and earth? I remember blue/brown/green striped in the early 70s but twin and earth was still red/black well into the 80s. Father-in-law was an electrician

[Reelman]

...and told me it was official.

Peter

[jay_oldstuff]

red black twin and earth was allowed up to the early 2000's 2002/3 i think, the replacement brown blue was being sold and used for a number of years before that.
it also changed the three phase codes from red yellow blue phase colours and black neutral, to brown black grey phase colours with blue as neutral, a situation that has caught out a number of electricians.

Jay

[neon indicator]

Yes, the fixed household lighting, spur and ring mains changed from 2002 (introduction) to 2004 (mandatory).

Black and grey always seemed odd. Why not orange and purple or something?

[broadgage]

Black and brown were already well established as phase colours in Europe and therefore could not be avoided.
Grey was rather an odd choice and suprised a number of people, especialy as different European countries had formerly used grey as earth or neutral.

Orange was considered unsuitable as too similar to red, formerly earth in some countries.

I dont see why purple could not have been used, and believe that it was considered.

I think that all phases should have been brown, numbered or lettered if required.

[ppppenguin]

Originally Posted by broadgage

I think that all phases should have been brown, numbered or lettered if required.

I think this is still allowed. As it was with red under the old colour scheme. If you are using MICC "Pyro" cable then numbering always was a common way to identify the phases.

[ThePillenwerfer]

I've found this in some old 30s textbooks:-

"In standard three-core flex, the three cores are coloured red for live wire, grey, white, or black for neutral, and brown for earth." [Italics in orginal].

The 'Harmonised' code for cable confuses me still but luckily rarely come across it. The first time I saw the new triple and earth I thought I was seeing things; it's nearly as bad as BT's spotty stuff.

- Joe

[twocvbloke]

Regarding the US/Canada colours, as mentioned there's the Black Live and White Neutral (often referred to Hot and Cold), with Green Earth, there's also flat cables (which are basically T&E, but with stranded wire) that are used as extension cables, see pic below, with these they have no coloured cores, instead they have a smooth coat over the Live and a Ribbed or Textured coat over the Neutral, and the Earth runs down the centre within a green sheath. This is not to be confused with DC cables that use the Textured side as Positive and smooth Negative...

I only learned there was a difference between the L and N sides on a couple of clamp-on lamps I bought from the US, I wired them back to front in a UK plug and ended up switching the Neutral, so holding the metal shade and grabbing the CFL inside made the CFL light up as power was running through the bulb and then through me to Earth!!!

Also, cables such as polarised small appliance cables have a tracer on the outer sheath to indicate the position of the Neutral, no idea why they need that feature, but they do it anyway, as shown in the pic below...

And just to add some more colour coding to the mix, the wall sockets, switches and other terminals over there are also colour coded, Brass for Live, Silver for Neutral and Green (painted usually) for Earth, although they also label them too, just incase...

[bluepilot]

I once helped someone move into a flat where the wiring was the old standard black and grey with red for earth. The earth hadn't even been connected so nothing in the flat was earthed properly. She wanted a few extra sockets installing, so I thought I would do her a favour and connect up the earth as well. I ended up getting things in a complete mess. It seems someone had drilled a hole in the wall and hit the neutral wire at some point. From that point onward, the red had been used to replace the neutral. In the end I just put everything back the way it had been and suggested she get the place rewired.

[neon indicator]

And the value of distinguishing neutral and earth on the two pin US blade plug?