Part P: mixing colours

It will be dropped from BS7671. As for what's "permitted" and where, that's a more complex matter.

Reply to
Andrew Gabriel
Loading thread data ...

What seems to have happened is that good ol' BS 6004 has been amended so that (in addition to the new core colours) the only permitted sheath colour for ordinary 70 deg. C twin & earth is *grey*. The CMA designation changes from 6242Y to 6242YH (6243YH for triple & earth), where the H stands for 'harmonised.'

The sheath colour *white* now indicates a new type of flat twin or triple & earth cable to BS 7211. This is a low-smoke zero halogen (LSOH) cable with a 90 deg. C conductor temperature rating and therefore higher current ratings (voltage drop etc. permitting). The CMA designation for this is 6242BH (or 6243BH). I'd expect this to be quite a lot more expensive than 6242YH, BTW.

More info here

formatting link
data sheet here
formatting link

Reply to
Andy Wade

I guess we could ask the same q about that notice: what even vaguely competent person would need to be informed in advance about the color mix??

NT

Reply to
bigcat

therefore

Screwfix do 6242B, old colours 2.5 t&e =A335.99 for 100 meters, as opposed to=20 2.5 t&e 6242YH for =A321.79 per 100 meters

Reply to
andrewd909

Sounds like profiteering to me.

Reply to
Dave Plowman (News)

Why? Those prices don't sound unduly high, and the LSOH material is much more expensive than ordinary PVC.

Reply to
Andy Wade

The strange thing about having to label whin mixing the different colour cabels is that they have been used in appliances and have been mixed in ceiling roses for years

Reply to
andrewd909

Ah - missed the suffix.

Reply to
Dave Plowman (News)

But there is a distinct difference between 'Flex' and *hard* wiring.

Reply to
:::Jerry::::

They used to be the same, but were changed in the name of EC harmonisation

- so goods could be sold in any country. Plugs excepted, obviously.

'Hard' wiring should have been changed at the same time. Absolutely no reason not to.

Reply to
Dave Plowman (News)

,

different

wiring.

harmonisation

Surely it was nothing to do with the EC (as in EEC / EU), the change pre dates our entry, although it might have been an agreed western Europe change IYSWIM.

I was always under the impression that the change of flex conductor colour change was to make mistakes less likely were untrained and possibly colour blind people were wiring up domestic plugs and appliances etc.

Reply to
:::Jerry::::

I never have understood reasoning. I mean, once upon a time Red (commonly signalling danger stop etc)= live Black (near enough neutral I suppose) Green (OK,opposite of red)

now Electric Blue Green/Yellow stripes make me think of wasps Brown (er? Earth?)

Reply to
quisquiliae

The idea was to make them obvious to the 1 in 3 males with a degree of colour blindness. In poor lighting, those people will not differentiate between green and red. Hence the green/yellow earth which someone totally colour blind will identify - swopping the others ain't life threatening.

Of course if people don't learn the colours but rely on gut instinct it makes no difference.

Other countries use black as live. White as neutral. Not sure about anything other than green as earth. But I'll bet it happens.

Reply to
Dave Plowman (News)

Brown is a warm colour Blue is a cold colour Green and yellow is dog piss on the lawn

Owain

Reply to
Owain

Look at it another way: the CU label for single-phase is already a concession. The requirements for 3-phase work are more onerous, requiring marking both old and new conductors with L1, L2, L3 & N marker sleeves at every junction between old and new colours, as well as the label.

BTW you can get the labels from RS; stock no. is 483-3517.

Reply to
Andy Wade

The Germans used to use red for earth. Anyone unaware of this and trying to fit a UK plug to a German appliance would connect its earth wire to the live pin of the plug! Yes, there was a need for harmonisation...

Reply to
Andy Wade

I came across a three phase supply in the Middle East where L1-3 and N were all black ! Fortunately not that common out there, most countries in that region have actually adopted (pre-April 05) UK practice, including BS1363 etc sockets.

Earth is green/yellow, (very yellow if you look out of the window :-) )

Reply to
Mark Carver

Red wire for Redcurrents

Black wire for Blackcurrents

And Green wire for the Green gauges.

Simple eh?...

Reply to
tony sayer

Yep, the harmonised colours also can help people remember where each wire goes in a 13A plug top:

B(ottom)R(ight) own B(ottom)L(eft)ue

you guess the other one!

Reply to
Dave

HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.