Has anyone come across this type of cable for a submain.

[jonesyk28@gmai]

hello I did an EICR today on a flat probably about 10 years old. everything fine except the usual C3s for non rcd protected circuits and for plastic boards etc. my question is has anyone come across the type of cable I found going from 80mcb near cut out to con unit in the flat. at first I thought it was 3 core 4mm swa until I open up the con-unit. Ive been sparking since 2004 and aint ever seen this type of cable.

the brown core is 16mm
there are 7 x 2.5mm blue cores whichs equates to 17.5mm
and theres 4 x 2.5mm bare cores resulting in 10mm

The submain does disappear in to wall so I wanna know if I just treat this like I would of if it was 16mm twin and earth sub main and put c3 down for not rcd protection to cable

this is the first time I have ever posted anything on here so if I'm doing anything wrong please let me know

 

[snowhead]

Split concentric as featured on another post today;

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[westward10]

Those neutral and earth bars are inadequate to terminate those conductors. They should be in the same terminal, the earthing conductor would only appear to have two strands terminated.

 

[jonesyk28@gmai]

Split concentric as featured on another post today;

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View attachment 60308

thanks for the reply much appreciated

 

[davesparks]

That is split concentric cable, no it does not satisfy the requirement for an earthed metallic screen or armour as most of the concentric conductor is connected to neutral, not earth.

Plus of course there's the other obvious issues in the pictures that need to be coded.

 

[Rockingit]

Out of interest, where is this sitting in relation to the meter? Reason for asking is because if it's actually part of a Building Network (so, what could be construed as DNO) then I believe it's a bit of a grey area as to what is the relevant applicable standard. Either way it's a dog's dinner, and that's probably an insult to the chef too!

 

[Julie.]

Split concentric cable, but is prohibited in this application.

I don't know what the earthing arrangement is, but it's tn-s, tn-c-s, or tt.

Since the earth is re-combined with the neutral (and then split at the cu ) the system has become

Tn-s-c-s
Tn-c-s-c-s
Or tt-nc-s

All of which are prohibited!

If the split-con cable was used on the tn-c incomer and finally split to tn-c-s once then it would be valid, however usually only the dno can do this, sort of different if it's a private transformer

 

[westward10]

You can use split concentric the cpc and neutral are separate but not concentric.

 

[Rockingit]

Split concentric cable, but is prohibited in this application.

I don't know what the earthing arrangement is, but it's tn-s, tn-c-s, or tt.

Since the earth is re-combined with the neutral (and then split at the cu ) the system has become

Tn-s-c-s
Tn-c-s-c-s
Or tt-nc-s

All of which are prohibited!

If the split-con cable was used on the tn-c incomer and finally split to tn-c-s once then it would be valid, however usually only the dno can do this, sort of different if it's a private transformer

say what?! Slowwwwly.....

 

[davesparks]

Split concentric cable, but is prohibited in this application.

Nonsense, split concentric is permitted in installations.

 

[Julie.]

say what?! Slowwwwly.....

At the incomer the cores have been split to L, N, and earth - you can see the three cables coming in.

This split concentric cable joins the N and E together - which is prohibited (joined quite well or fairly poorly depending on which outer wires are used at each end).

In effect this additional combining of pen gives the silly earthing arrangements

 

[davesparks]

Since the earth is re-combined with the neutral (and then split at the cu ) the system has become

the earth is not recombined with the neutral, they are seperate.

 

[Julie.]

Nonsense, split concentric is permitted in installations.

Only in certain installations, but not the way this has been done

 

[davesparks]

The split concentric cable joins the N and E together - which is prohibited (joined quite well or fairly poorly depending on which outer wires are used at each end).

No it doesn't, it keeps the N and E seperate, that's why it is called split concentric, the outer concentric conductor is split into two different conductors.
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Only in certain installations, but not the way this has been done

By which rules and what installations?

 

[Julie.]

No it doesn't, it keeps the N and E seperate, that's why it is called split concentric, the outer concentric conductor is split into two different conductors.
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By which rules and what installations?

Yes, but usually they are separately identified - these don't look to do so - it could be that only one set of outer wires goes to neutral, and the other to earth, but as I see that particular instance such segregation isn't guaranteed, it looks like a random selection of outer wires split between n&e rather than proper split.

The neutral wires usually have continuous insulation, it looks to me that its sleeved - on my phone anyway

 

[mattg4321]

Think you’re wrong on this one Julie.

That looks like split concentric to me. The neutral comes insulated blue and the cpc is bare

 

[Julie.]

Think you’re wrong on this one Julie.

That looks like split concentric to me. The neutral comes insulated blue and the cpc is bare

That would be what I would expect, but it looks like sleeving to me, if it isn't and it has been split correctly, then my bad.

 

[davesparks]

Yes, but usually they are separately identified - these don't look to do so - it could be that only one set of outer wires goes to neutral, and the other to earth, but as I see that particular instance such segregation isn't guaranteed, it looks like a random selection of outer wires split between n&e rather than proper split.

The neutral wires usually have continuous insulation, it looks to me that its sleeved - on my phone anyway

They are seperately identified, the blue cores insulated cores are connected to the neutral bar and the bare earth cores have been sleeved and connected to the earth bar.

 

[Julie.]

They are seperately identified, the blue cores insulated cores are connected to the neutral bar and the bare earth cores have been sleeved and connected to the earth bar.

Perhaps it is me and my phone, but it looks like sleeving on both n&e to me, if not and it's been done correctly then I stand corrected.

 

[mattg4321]

I’d have money on it that it isn’t sleeving