overhead incoming supply TT TNCS?

J.C.E · Oct 27, 2017

Looked at a rewire for a 5bed house reno this morning
bit of a odd setup!

so the house is supplied overhead- see pic 1- 2cores through the roof in loft
into a 60a fuse
then what looks like a 16mm T+E- but cpc (if one) is not used
this travels some meters (at a guess 10m) down to the ground floor- appears to be clipped as apposed to burried in wall.

this then goes into a 2nd 60a fuse (see pic 2)- see a 16mm G/Y cable- joint to the neatral- acting as the main earth.

the ze reading at the c/u is 0.22 with the main bonding dissed

few points:

1)the 20m run from loft to ground floor is un-metered and should be RCD

2)the wall that the 2nd 60a fuse+meter+c/u is planned to be knocked down anyways- so he needs me to remove electrics from there

3)am I right is saying this is a TNCS due to the reading- although on first impressions assumed a TT overhead?

4) would be acceaptable- to get rid of everything and start again-
so head in loft>> meter right next to it>>into new switch fuse iso>> swa sub main into a new consumer unit in a more accessible cupboard on 1st floor

[ElectriciansForums.net] overhead incoming supply TT TNCS?

Strima · Oct 27, 2017

I'd be requesting the DNO to come out and sort out their supply. I doubt they'd go for a meter in the loft due to access even if they fit a smart one.

The Ghost · Oct 27, 2017

If you did max demand on that box alone, then add whatever the submain is supplying seems like quite a load. Is that lead covered the supply cable in the loft?

The Ghost · Oct 27, 2017

Ok so those two black cables go to the off peak supply/timer Think I can just see the PME label under the tails but isn't that supply to off peak the wrong side of the meter? Oh yeh can see the label above now, just ignore me.

J.C.E · Oct 27, 2017

Vortigern said:
Where does that black cable go to under the earth cable in the fused connection? Doesn't look like TN-C-S If it's overhead you would think TT but then how is that earth to consumer unit supplied. If you did max demand on that box alone, then add whatever the submain is supplying seems like quite a load. Is that lead covered the supply cable in the loft?

goes into that meter on the ajoining wall

then 16mm cable did look like lead- and had that black stuff twisted around the end

J.C.E · Oct 27, 2017

Vortigern said:
Ok so those two black cables go to the off peak supply/timer then maybe they did allow TN-C-S there then. I have had it agreed before to do that by the DNO in more remote places with TT.

they are actually having a loft ext- that side of the roof is not changing- will just be boarded over- but it will be more accessible than it just being a attic- then I could suggest a access panel to the meter and head

The Ghost · Oct 27, 2017

Looks very well built house with the boards over the rafters and so on.

J.C.E · Oct 27, 2017

Vortigern said:
If you did max demand on that box alone, then add whatever the submain is supplying seems like quite a load. Is that lead covered the supply cable in the loft?

the sub main is a 2nd c/u on 1st floor
think it was previously 2x flats- but it will now be one house- max demand wise- 60a will be fine- minmal points, gas cooking, gas CH

Trickster81 · Oct 27, 2017

The cut out by the meter should be a RED link as the main fuse is in the loft. Moving the meter would be down to supplier and Dno agreeing.

Can’t see how it can be PME as no earth at head in attic. So it would have to be TT.

Looking clearly it is PME but if wall is being taken out DNO need to be called to move supply, and should fit a nice new series 7 or 8 cutout. Correctly labelling and identifying what earth you have.