ECN Forum Forums General Topics of the Trade Non-US Electrical Systems & Trades New UK colour code

Well, it will mean the colors joined as follows:

Old cable <--> New cable

Red <--> Brown
Yellow <--> Black
Blue <--> Gray
Black <--> Blue

The thread about sizing SWA cable and whether to use a separate conductor as a parallel earth has also got me to thinking about the colors.

At present, a 2-core (plus earth) cable has red & black, 3-core has red, yellow, blue, and 4-core has red, yellow, blue, black.

When using a 3-core for a single-phase line, I think most electricians follow what I do and tape the blue wire black to use as the neutral, and use green/yellow tape on the yellow to use as earth.

I assume when the new colors come in that 3-core cable will be brown, black, gray. My bet would be that for single-phase use most will associate black with neutral anyway and tape that conductor blue, leaving the gray to be re-identified with green/yellow for earth.

Thankfully in Ireland Black has been banned in 3-phase installations for quite a while. I wonder if the ETCI has been planning this change for quite a while?

The only place you'll find black as "N" is in older domestic single phase installations.

Hopefully this will mean no major problem.

I don't know why they didn't simply introduce new cables with stripes to identify them as new system?

E.g. the new 3 phase cables could all carry a red stripe on all phase and neutral cables.

I guess striped conductors might have been a good way to identify the new cable. I'm not sure about red though -- Could there have been room for confusion in the Germanic countries in which red might still be associated with earth?

I still think that CENELEC could have decided on a better combination of phase colors than brown/black/gray.

Yeah, orange had been better than grey. But I think you should be barking up a tree closer to home:

Andy Wade wrote in uk.d-i-y

"The adoption of grey represents a battle won for the UK by the IEE[*] in CENELEC. The rest of Europe uses various combinations of brown and black for phases. The IEE wanted to keep three distinct colours and proposed grey as the 3rd phase colour. It's now clear that they've got their way.

[*] The joint IEE/BSI national committee (JPEL/64) to be pedantic."

Hmm, so gray is there at the behest of the British contingent -- I hadn't realized that.

The orange that you suggest might have been a good idea, and certainly a better choice than gray. There must surely be gray still in use as a neutral in older installations in Germany, so they'll be stuck with the awkward dual-use of the color (just as with blue in Britain).

If they were trying to propose three distinctive colors, I wonder why nobody proposed that we don't use both black and brown? Or was this proposed and rejected?

If we accept that brown is going to be one phase and orange another, then perhaps yellow would have been the logical choice for the remaining phase. It's already in use as such in the U.K., and we'd then have the same BOY coding as used for 277/480V in the US, albeit with a blue neutral.

I'm just thinking out loud here -- Too late to get them to change it now, I guess.