ECN Forum Forums General Topics of the Trade Non-US Electrical Systems & Trades Strange Cable types?

I still see some of the old lead-sheathed cable in use from time to time, although it's quite rare now.


In old houses, lighting circuits are the most likely places to still find really old wiring methods in use. So many houses have had the circuits for sockets and other devices rewired in more modern times, but lighting circuits are often still original: Rubber singles in thinwall conduit from the 1930s, for example.
Is this a change back to white though?

The old British Standard used red/white/blue. Phase B was changed from white to yellow in 1964. Curiously though, white continued as the phase B color in flexible cords after the fixed cables went over to yellow.

As the adoption of green/yellow for earth (in flex only) was in the pipeline, I wonder whether this was done deliberately to avoid having yellow on two conductors. If so though, it would have made more sense to just leave fixed cables with white as well!

I don't have all the intermediate amendments here, but the 1966 IEE Regs. still show white for flex, yellow for fixed cables. By 1970 though, flexes changed to the European colors, with brown for all three phases.



[This message has been edited by pauluk (edited 06-23-2005).]

Paul,
Ahaa!, now that is the real question.
I've just been looking at the 1961 Regs I have here and it says yellow as the B phase in 3 phase cables.
I'll have a look at the 1935 Regs at work tomorrow to see what that says.
I don't think that they used colour coding back then, it's hard to say, I'm guessing a numbering system.
Who knows?.

Here in Austria where conduit was used they didn't have a color coding until the 1970ies... I've seen a huge main panel with the main fuses for several apartments in a 1900 building. The panel has 1957 scribbled on the door. The circuits for the apartments are wired in various colors, but always the same for all 4 wires, that means one apartment has purple phases and neutral, one has blue, one white... grounds are a mixture of red and mostly yellow-green, so I assume they are a later addition. Some day I gotta take a picture of that panel. It once started as a real nice huge Diazed II and III panel, all wires nicely bundled and everything. Now it is one big mess. Many circuits have been cut off as apartments were joined together and split up again, covers are missing, empty fuse bases without screw caps, wrong labeling,... it's the house with the lead cables and phone patch panel.

2 words Trumpy, at least as regards the older stuff in the UK. Plasticiser Migration.

Had to deal with some today on a kitchen remodel, the plasticiser had leaked from the cable where it had been run under the plaster behind a gas stove, the cable sheath was covered in sticky yellow goo, and the internal core insulation was brittle as bakelite. Lovely

OK Paul,
Regulation 44 :(Of 1935)
One thing that I have learned guys, is the fact that I love reading old Regulations.
The oldest we have here is the 1915 (First Institution) although Reefton (do a Google on that) was the first place in the Southern Hemisphere to have a reticulated power supply back in 1890 (I think).
I had to get out and do some work though, I could have read for hours though.

[This message has been edited by Trumpy (edited 06-24-2005).]

Comments and picture submitted by Chipmunk:



Thanks Chipmunk!.

Just merely for comparison's sake, here is the 2.5mm2 we use here in New Zealand:



All 3 conductors are stranded (7/0.67), they don't come pre-twisted like that, I just twisted them up to make the pic a wee bit neater.

As I've mentioned before here, our TPS (Tough-Plastic Sheathed) cables have a metre-marking printed on the outer sheath, to tell you how much cable is left on the reel.
Here's what it looks like:

Hmmm..... Why would somebody have done it that way, I wonder? If there is a need to identify circuits belonging to each apartment (maybe in a floor/celing void where there are conduits for the apartments both above and below), then I would mark the actual conduits at strategic points with tape or paint.

Yes, on 2.5 cable the earth is 1.5mm. Believe it or not, I still haven't actually seen any of this yet! (The local warehouse is stocking it, but they still seem to have miles of red/black.) I've installed some SWA with harmonized colours, and single brown/blue meter tails, but not the new T&E yet.

I remember us discussing this before. The main differences between this and UK cable seem to be:

1. You have the phase conductor in the middle.

2. Your 2.5 is stranded, ours is solid.

3. You have a sleeved earth. (Is that plain green, or is there a yellow stripe we can't see?)

4. You have a full-sized earth.


O.K. then. I can't go back that far on the British Regs., but here's the appropriate section from 1955 on identification of conductors:

Table 7 specifies:

Earths = Green
Neutral = Black
Live of 2w cct = Red
Phases on 3-ph cct = Red, white, blue

And for DC:
2w positive = Red
2w negative = Black

3w positive = Red
3w neutral = Black
3w negative = White

It also specifies that the outer -- either positive or negative of 2w DC cct. derived from a 3w cct shall be red. That's a little offputting when red can be negative, but consistent with red being the live on a single-phase AC circuit no matter which phase it's derived from.

The standards referred to specify 1, 2, and 3 for phases with 0 for neutral.

I'm not sure of the contents of B.S.158.


{ Edited for typo! }


[This message has been edited by pauluk (edited 06-29-2005).]

Re old wiring in wooden channels, I also found the following in the 1955 Regs. while looking for the above:


Reg. 606 basically sets out the standard sort of cables: PVC or rubber-insulated, impregnated paper, mineral-insulated copper-sheathed, etc.

Nothing like that... It's just each circuit running in its own conduit up from the basement to the meters for all shops/apartments in the basement and on the ground floor. And it's only the three-phase circcuits that are coded like that, the single phase use the "whatever they had" scheme.