Loft Consumer unit

[frank999]

Can you run 10mm2 T&E from the mains isolator into a consumer unit, or do you need to use Tails.

If you run the 10mm2 T&E up a wall (as opposed to - in a capped channel), can someone advise what sort of conduit would be required ?

Thanks

 

[FDJ]

Can you run 10mm2 T&E from the mains isolator into a consumer unit, or do you need to use Tails.

If you run the 10mm2 T&E up a wall (as opposed to - in a capped channel), can someone advise what sort of conduit would be required ?

Thanks

Meter tails are usually 25sq.mm so 10mm is too small to be fused 100A
You would normally run singles in conduit, not T&E.
Frank

 

[AndyPRK]

Running SWA from the existing CU is probably the answer.

 

[flameport]

Why do you want a consumer unit in a loft?

 

[frank999]

I will split the house into 2 flats, I'm trying to lay cabling for the new loft circuits in mind of this, also the existing consumer unit lacks room for any more circuits.

If I simply replaced the old Consumer Unit I assume the electrician will need to test anything he connects to it, even though those circuits may have been working fine on the old consumer unit.

If someone refers to the cable running from the main fuse to the Consumer Unit:
16mm2 as a minimum if 60/80A main cut-off fuse
or
25mm2 if 100A fuse
I assume you buy a CU with an inbuilt fuse of appropriate rating, 60/80A for a flat, 100A for a house ?

 

[RF Lighting]

 

[frank999]

LOL, yes very funny, but that is not the reason why ...

 

[JohnW2]

I assume you buy a CU with an inbuilt fuse of appropriate rating, 60/80A for a flat, 100A for a house ?

You might assume that, but I think you would be looking for a very long time in an attempt to find where you could buy "a CU with an inbuilt fuse" of any rating - and, in any event, I'm not sure what purpose you think that fuse would serve. It sounds as if you need some expert assistance.

Kind Regards, John

 

[frank999]

Sorry I should have said 'isolator'.

What are incoming domestic supplies rated at (ie the fuse before the CU) - or do they vary.

"You would normally run singles in conduit, not T&E" ... any particular type of conduit ? ie metal or plastic.

 

[JohnW2]

Sorry I should have said 'isolator'. What are incoming domestic supplies rated at (ie the fuse before the CU) - or do they vary.

You seem to have answered that question for yourself above - usually 60A or 80A, sometimes 100A. The required rating of the 'isolator' ('main switch') in a CU depends upon the total potential loading of the CU, not the size of the upstream fuse.

"You would normally run singles in conduit, not T&E" ... any particular type of conduit ? ie metal or plastic.

If they were single-insulated singles, you would have no option but to run them in earthed metal conduit. If they were double-insulated (aka 'tails'),the choice would be yours. There's nothing intrinsically electrically wrong with using (10mm² or 16mm²) T&E to feed a CU, except that the size of the CPC ('earth') may not be adequate for the purpose - whether that were a problem would have to be determined by calculation.

Kind Regards, John

 

[Taylortwocities]

The DNO (supply company) mandate a maximum distance of cables running from the meter. This is usually 3 metres.

Anything longer than this will require you to install a switch fuse.

In any event, if you were running only 10mm cable from the incoming to upstairs, then you would need to select a CPD at the supply end that would break before your 10mm cable caught fire.
The residents of your property will appreciate that this work is done correctly as they will hate to spend years in a serious burns unit. (No jokes about Scottish poets please).

Your other consideration re 10mm is volt drop. How did you decide on 10mm? Do you have drum of it left over from another job? This is not how we design electrical installations..

 

[JohnW2]

The DNO (supply company) mandate a maximum distance of cables running from the meter. This is usually 3 metres. Anything longer than this will require you to install a switch fuse. In any event, if you were running only 10mm cable from the incoming to upstairs, then you would need to select a CPD at the supply end that would break before your 10mm cable caught fire.

Indeed. It's quite difficult to work out what the OP does, and does not, know (which is why I suggested he needed expert assistance) since, despite his initial mention of 10mm² cable, he went on to write:

... the cable running from the main fuse to the Consumer Unit: 16mm2 as a minimum if 60/80A main cut-off fuse, or 25mm2 if 100A fuse

There is, of course, apparently still a 'DNO requirement' for an additional switch-fuse for runs >3m (or whatever) from meter, but the electrical justification for that is less clear (at least to me) if (e.g. per OP's figures above) the cable's CSA is such as to be adequately protected (from 'catching fire') by the DNO's fuse.

... but I definitely still think that the OP needs expert assistance

Kind Regards, John

 

[frank999]

Thanks, just trying to plan for the eventual split into flats.

I have a 45A isolator fitted after the meter, I am not sure the incoming from the street (ie 60/80A or 100A).

UK Power Networks advise me I would need a new supply installing, trenches dug to street etc. and that they wont split the supply, is that right ?

 

[JohnW2]

Thanks, just trying to plan for the eventual split into flats. I have a 45A isolator fitted after the meter, I am not sure the incoming from the street (ie 60/80A or 100A). UK Power Networks advise me I would need a new supply installing, trenches dug to street etc. and that they wont split the supply, is that right ?

UKPN may well be right. If (as is likely) you have a 60A or 80A supply, it's fairly unlikely that would be adequate for supplying two 'dwellings'/ 'households'. You need someone to make a proper assessment of the requirements for the supplies to the two sub-dwellings, and then move forwards from there to determine what is required/practical. Given the fact that you're talking about notifiable work, and given your apparent level of knowledge, you're going to need to involve an electrician, so IMO you might as well do that now.

Kind Regards, John