Colours Of Conductors.

[7029 dave]

Just looked at a thread, got me thinking of old imperial cables etc. The mention of the old red white and blue 3 core pvc no cpc got me thinking about a situation. I remember because have only seen it once in 37 years on domestic installations.

Block of flats in East finchley North London,Local authority full conduit system, on the lighting circuit all live conductors were white . Anybody else ever seen this in their time.?

 

[Risteard]

It was acceptable to wire single phase circuits to the phase colour, eg red, yellow or blue on larger installations but only time I have seen it on domestic was when an Octoflex modular wiring system was used where all the returns from the lighting switches were yellow.

Actually it was never permitted for final circuits - only for distribution circuits (submains).

 

[ipf]

Doing an industrial EICR and found a socket in a conduit system with the live ring conductors blue and yellow...with a red spurred. Can't see the problem though, I knew what they were without having to think about it and it tested fine.

 

[Risteard]

Doing an industrial EICR and found a socket in a conduit system with the live ring conductors blue and yellow...with a red spurred. Can't see the problem though, I knew what they were without having to think about it and it tested fine.

I can see a problem. What is a circuit wired with blue and black live conductors? Is it L3 and neutral or L2 and neutral with either swapping between phase and neutral?

It is however permitted by ETCI Wiring Rules in the south of Ireland.

 

[ipf]

I can see a problem. What is a circuit wired with blue and black live conductors? Is it L3 and neutral or L2 and neutral with either swapping between phase and neutral?

The neutrals are 3 blacks. The lives R,Y,B.
It's an old installation, all wired in old colours and not a chance of any alteration, and if someone can't get their head round the situation they are either thick as pig s*** or from across the sea...in Europe somewhere..
Use a Reg for a situation.....after weighing it up.

 

[Lucien Nunes]

But Risteard has a point there, that a blue/black circuit has become ambiguous since harmonisation. In a 3-phase circuit, you can tell which version of colours applies, so you can identify which of blue or black is neutral. But in a single-phase circuit with blue and black only, the absence of the other phases makes it impossible to know with certainty.

I like the setup in France, where line conductors can be any permissible colour other than blue or G/Y, which makes lighting wiring much more obvious. For example, brown for supply, red for S/L, a pair of oranges or purples are popular for strappers. You can 2nd-fix a 2g 2-way switch on a conduit system and know the functions of all the conductors more or less straight off.

 

[ipf]

Yes, of course he has a point, but it depends on the situation and the possibility of problems occurring.

 

[sinewove]

Any reason why an old reel of black d/s could not be used with brown tape at the ends,since black is used in 3c and e?
Regards,s

 

[telectrix]

typical yorkshire, save a shilling whenever. you'd need to sleeve the red with brown and the black with blue. sod tape. it falls off in time.

 

[sinewove]

typical yorkshire, save a shilling whenever. you'd need to sleeve the red with brown and the black with blue. sod tape. it falls off in time.

Why sleeve the black with blue if black is an official phase colour?

 

[telectrix]

because black is no longer neutral.

 

[7029 dave]

Black is now a phase colour. I wish we were still red yellow blue, black neutral.?!!

 

[davesparks]

Any reason why an old reel of black d/s could not be used with brown tape at the ends,since black is used in 3c and e?
Regards,s

What has 3 core got to do with anything?

What exactly do you mean by d/s?

I assume you mean singles?

 

[sinewove]

What has 3 core got to do with anything?

What exactly do you mean by d/s?

I assume you mean singles?

Black singles with a grey sheath.3 core and earth contains a black core.

 

[davesparks]

Black singles with a grey sheath.3 core and earth contains a black core.

I get you now, never seen it referred to as d/s before.
I still don't see how 3core relates to this? The black in 3core denotes core number 2, the singles by definition do not have a core number 2 therefore a comparison is not possible.

I see no issue with sleeving it with whatever colour you need.

 

[PRR]

> with a black neutral.

Interesting history of technical materials here.

Early US wiring was bare. To reduce death it was 100V. Soon delivered as +100V/0/-100V to give twice the power without twice the copper. The "0" was nominally tied to dirt.

Rubber insulation came a little later. (Metals and wires were more mature than rubber production.) The rubber was heavily cut with lampblack for toughness and economy. All Wires Were BLACK.

Interestingly as late as 1915 some argued that an UN-grounded system is safer. Easy to show in a lab. But in the wild there are no un-grounded systems. There is always some leakage, not enough to notice at the generator, but ample to kill a grounded person on the other leg. (Also longer lines with more lightning exposure fared very much better if frequently tied to dirt.)

That balderdash was cleared up. A groundED entrance conductor was first allowed and then required. And the inside wiring had to have that leg of the line "Identified". Since all rubber was black, the rubber was painted. Probably zinc-oxide, oil, and benzene to "bite" the rubber. Didn't cover or stick so well. Now we had the black "hot" wires and "Identified" (groundED) wires with bits of white/grey flaking off.

So:
Black = Hot
White(?) = groundED ("Neutral")

Sadly this crap paint continued long into the 1940s. Both my parents and I owned houses where the Identified wires were far from White and often pretty darn black. Sometimes we had to fall-back on the old plan: All Wires Are Black.

This is also sad because durable White Rubber was available in automobile tyre side-walls.

Like car rubber, electrical rubber breaks-down over the decades. My parents were lucky to sell-out before their rotting wired burned the place down.

PVC and similar plastics made the difference. Any color is pennies per mile cost, so all primary colors became available, and have usually proved durable inside conduit or cable.

FWIW, "Green" (groundING) conductors were rare here until the 1970s, though for a long time we pretended that metal armored flex was an OK Ground.

BTW: I have seen lots of gear where all the internal wiring was white. Utter madness to trace and debug.