Can anyone guess an work this out

[axel132132]

An

anyone tell me what type of cable this is? Its hv cable underground for electric board but never seen it before and engineers have no idea its rated at 11kv - the outer stranding bells through to the inner core but what are the papers between about

engineers are confused say its not a screen or a strenghtening

ideas anyone? Its old around 1910 tape armoured lead covered cable

 

[telectrix]

google concentric cable.

 

[Deleted member 9648]

http://www.cablejoints.co.uk/upload/Concentric_Cablee___LV_Cable_Jointers_&_Jointing_Procedures.pdf

 

[GEOFF S]

Triplex Bs7870

Not 1910 though.

Cheers

 

[Lucien Nunes]

You say it's 11kV rated cable, is it being used at 11kV? It sounds like the cores have metallic screens that are supposed to be earthed but have been paralleled with the cores. This could lead to insulation failure as the stress is too high on the outer paper. These days there would be a layer of semi-conducting plastic screen but you just have the copper. If you are convinced they are not screens, could it have been for a dual-voltage circuit?

Re. the jointing pdf, that relates to LV cables which don't have the same requirements to control the radial voltage gradient as HV cables do.

 

[Biff61]

Hi new to the site and just introduced myself on the newbie thread.
Looks like bog standard 6 to 11 kv paper insulated with copper screen and out PVC insulation, check out some of the cable manufacturers sites especially prysmian, they have a very similar cable on their site.

 

[Engineer54]

Is this a 3 core cable or 3 single core cables?? Do you have any other photo's such as showing breakout (if 3 core cable)??

 

[Engineer54]

You say it's 11kV rated cable, is it being used at 11kV? It sounds like the cores have metallic screens that are supposed to be earthed but have been paralleled with the cores. This could lead to insulation failure as the stress is too high on the outer paper. These days there would be a layer of semi-conducting plastic screen but you just have the copper. If you are convinced they are not screens, could it have been for a dual-voltage circuit?

Re. the jointing pdf, that relates to LV cables which don't have the same requirements to control the radial voltage gradient as HV cables do.

Don't know about you, but that insulation on the cores doesn't look to be upto containing a 11KV rating. I've seen a good bit of MV cable types, but can't say i've seen this particular example before.
Perhap Tony may shed some light on this cable!!

 

[Engineer54]

CU/XLPE/CWS/WB/PE 6.35/11KV - TRIPLEX - BS 7870-4.10 - Nexans


Just found this, ....seen it before but never used on any of my projects. That insulation just doesn't look up to the job of insulating 11KV.

 

[mechelec]

Has it got an aluminium sheath ? If so it could be consac cable. If it is lead sheath it could be an old DC cable running at 11KV.

 

[telectrix]

as it's obviously 3 phase, could it be that they used the oute and inner as parallel conductors, as , in your OP, you stated that they belled out to each other?

 

[Knobhead]

Anyone spotted the Raychem heat shrink?

If it was a 1910 11KV PILC TA I can assure you the papers would be a damn site thicker and there would be no screen.

Send the pictures to BASEC, if they can’t help no one can.

PS if it has been left like that for any while it will be ruined.

 

[Lucien Nunes]

So that's 3 or 4 of us all thinking it doesn't look convincingly like 11kV cable of that age. Where did this info come from? What is its present application? I wonder at the insulation thickness though because it's hard to see the scale in the picture, I started out visualising it with conductors of maybe 0.1 sq ins but maybe that's a trick of the camera angle.

 

[Knobhead]

All the 0.1” PILC I’ve worked on were 37 strand. I’m thinking along the lines of 19/.044 which would account for the size of the screen. Based on that the papers are way to thin for 11KV added to which the belting papers over the “screen” are far thicker than needed unless they are a conductor.
But I keep coming back to screens weren’t in general use until after the 2[SUP]nd[/SUP] WW.

 

[mechelec]

What is the network voltage ? A lot of the old DC networks were converted to 6.6KV that could account for the concentric construction ie + and - in each core. They may have been bonded together to increase current carrying capacity.

 

[telectrix]

What is the network voltage ? A lot of the old DC networks were converted to 6.6KV that could account for the concentric construction ie + and - in each core. They may have been bonded together to increase current carrying capacity.

that's what i was thinking in post #11. the doubling up to increase the CCC.

 

[Lucien Nunes]

Yes I'm sure you're right Tony, I just saw thick strands to begin with but realised that's not likely. I can't see how it would have been made for DC and then re-purposed for AC, unless it was 3-phase DC

and then it would only have been for LV, as HVDC was the province of special systems like the Oxford 2kV system.

I'm also keen to know the present working voltage.

 

[TJ Anderson]

You lot should have gone to specsavers. It has Raychem branded on it!! They were founded in 1957 so it is definitely after then.

 

[Beavstro]

Looks similar to the 95mm2 triplex I'm used to seeing. But a copper core rather than aluminium core. (More than likely due to costs) which we use on our 11kV systems.
I am still a sparky in training, but the copper "sheath" on the outside is connected to earth, and isn't used as a power carrier.

 

[mechelec]

You lot should have gone to specsavers. It has Raychem branded on it!! They were founded in 1957 so it is definitely after then.

That is the heat shrink they have put over the papers !!