Imperial Cable

[securespark]

I thought stranded imperial cable had stranded cpc's?

 

[Lectrician]

Not that size

 

[securespark]

I'm sure I've seen cable feeding lights with a stranded cpc.

Oh, hang on, could it have been 3/ .036?

 

[wingcoax]

Could be ,seem to remember being taught to wrap and solder that size.

 

[Stoday]

That's 3/.029 with 1/.044 cpc for lighting. Cheap & nasty used 1/.044 for lighting.

3/.036 was used for the immersion heater circuit

 

[securespark]

So 3/ .036 did have a stranded cpc then?

 

[kai]

I always thought ancient lighting circuits wired in 3/029 were never normally earthed back in those days, if you had a metal light then you would have had to run a separate earthing core alongside the 3/029 to earth the metal lamp etc.

That 3/029 with an inbuilt core must be very rare - indeed it may be a collector's item nowadays!

 

[RF Lighting]

Our house was wired in rubber insulated 3/.029 for the lights. It was twin and earth from the fusebox to the main joint box, and then twin with no earth out from there to each light.

 

[Paul_C]

Here you go, standard earth sizes in Imperial cables, from the 14th edition:

http://electrical-contractor.net/PC/IEE1966_TableD2.jpg

 

[Paul_C]

So 3/ .036 did have a stranded cpc then?

No. As per the table, 3/.036 had a 1/.044 earth. 7/.029 was the smallest size with stranded earth.

That 3/029 with an inbuilt core must be very rare

Not especially. Imperial cables were still in use when the 14th edition in 1966 specified earths to be run on all lighting circuits. And for years before that earths were still needed on lighting circuits where discharge lights were employed, or where metal light fixtures were not mounted out of reach, or where metal switches needed earthing.

 

[Stoday]

Used to have single black sheathed and single red plus E sheathed. The 1/.044 CPC was insulated green, so no need for sleeving. On the other hand the CPC of 7/.029 TW&E was not insulated IIRC.

 

[Paul_C]

n the other hand the CPC of 7/.029 TW&E was not insulated IIRC.

The ECC (as it was called then) was never insulated as standard in any size T&E. I hesitate to say it was never insulated, period, just in case there were ever some "specials" made!

 

[empip]

Don't be shy chaps - pros will know...

3/0.029" x 1/0.044" (cpc 0.98mm²)
3/0.036" x 1/0.044" (cpc 0.98mm²)

7/0.029" x 3/0.036" (cpc 1.97mm²)

7/0.036" x 7/0.029" (cpc 2.98mm²)

7/0.044" x 7/0.036" (cpc 4.59mm²)

7/0.052" x 7/0.044" (cpc 6.86mm²)

7/0.064" x 7/0.052" (cpc 9.59mm²)

Apart from final two, have measured real cable with trusty Moore & Wright.
-0-

 

[plugwash]

n the other hand the CPC of 7/.029 TW&E was not insulated IIRC.

The ECC (as it was called then) was never insulated as standard in any size T&E. I hesitate to say it was never insulated, period, just in case there were ever some "specials" made!

And I'm pretty sure the Australian equivalent of T&E has it insulated.

 

[Paul_C]

And I'm pretty sure the Australian equivalent of T&E has it insulated.

I've also seen cables in their catalogs which have an E-L-N arrangement of cores as opposed to the N-E-L in that picture (or perhaps I should say E-A-N instead of N-E-A as it's Australian). It also seems that their 2.5 sq. mm is stranded.