Old pre-wired black conduit

[lilman]

Does anyone happen to know the name of a type of wiring system I have come across in some flats (built in 1969). On first look it appears a bit like old TRS, with black outer sheath; but this is really tough and hard to cut. The conductors (imperial sizes in black and red, with a bare cpc in the centre)inside can be pulled through the sheath. I have been told it's probably some kind of pre-formed wiring system from the period, and required special back boxes etc. Anyone got a name or more info. I would like to know firstly out of interest and secondly what to put on my test sheets. Cheers

 

[binky]

Sure its not just age-hardened??? Don't think I've come across what you describe but anything from the 60s is got to be coming near to the end of its life.

 

[Evans Electric]

Sounds like one of the pre-wired systems that abounded in those distant times. There were quite few around one called Anaconda I think. They were always looking for an alternative to steel conduit , had to be quick ,cheap and rewirable. It will be PVC though, doubt if it needs rewiring, its just a carp system but its lasted 40 years.

Specs probably installed it as he,s really old.

 

[green-hornet]

There where a load of council houses built with the same stuff. It looks like oval conduit but has a hard rubber outer sheath, and looks twice the size of the cable it carries.

Most of them the outer sheath was ribbed along its length.

They normally connected to wylex inset cu's and the outer sheath was left external to most fittings. I can not remember any special fittings for them unless you count the bakolite stuff:^O

 

[lilman]

Sure its not just age-hardened??? Don't think I've come across what you describe but anything from the 60s is got to be coming near to the end of its life.

All IR tests +299Mohms!

 

[Pyro]

I have never seen the stuff first-hand, but I recall reading about the type of wiring conduit that you describe back in 1971 in the edition of "Modern Wiring Practice" that was current at that time. The system described had a 4-bore oval conduit, black, ridged and targeted at use in pre-fab low-cost housing construction. Any chance of some photos, Lilman?

Pyro.

 

[Andy™]

cant remember ever coming accross this stuff

 

[lilman]

Here is a photo of said cable

 

[Andy™]

ive seen this stuff before. i think its made of a plastic that has gone fairly hard over time. other than that, its still your basic T&E design. the conductors probably pull through because they are loose, it is in no way singles in conduit or anything

 

[Evans Electric]

I'm pretty sure it was supposed to answer the rewirable specification, whether it is possible is another question.

 

[green-hornet]

There is room in the sheath to allow a pull through, which was supposed to help in any re-wire.

However the idea never really caught on, modern twin and earths where by this time cheaper and easier to install.

The 2.5 version of this type of wiring was almost double the size of twin& earth.

I did some tests with my fluke which measures IR up to 500 and all the cables tested at max readings so I would say its good stuff, if hard to actually install.

 

[sparkyrj]

I actually installed something like this in the late eighties but cant remember the name.Also when i was an apprentice in the seventies i worked on an old peoples home in london that used it .It came in a pre made up loom and you just fixed the boxes in place on the shuttering before the concrete was poured.In both cases the cables were metric and we were using sizes up to 6mm.