Sub main cable sizes?

[stillp]

qualified person doing all the design (done)

Doesn't seem to be done.

 

[Curlewhouse]

 

[ban-all-sheds]

There are two classes of people, and only two, who can certify to Building Control that the work complied with Part P:

1. ...
2. A registered third-party certifier

So if you did appoint a registered third-party certifier before work began - and note that "work" includes the design, why are you not asking them these questions? After all, you are paying them.

 

[bernardgreen]

For what it is worth when I had a new supply installed in 2011 from street to new meter box I dug the trench and installed a duct ( the type specified by the DNO ) 32mm diameter. The DNO supplied the cable in the price for the connection. Aluminium core 6.6 mm diameter which is 34.2 mm² (π x r² ) and 12 metres long

Likewise in 1980 the DNO supplied the cable to the house we built and pulled it through the 50 metres of duct we had installed and back filled.

So for the mortgage I would put the down the cost of ducting and trenching and the estimated cost that the DNO have provided you with

 

[ban-all-sheds]

So if you did appoint a registered third-party certifier before work began...

And BTW, Curlew - if you haven't yet appointed one, you really need to crack on. Not only must you do it before you start the work, if that route to compliance is to work, there aren't very many - you might find it hard to find one.

 

[John D v2.0]

Being honest even if you do the basics yourself eg lifting cables and digging trenches, I think that would go in your favour, as most electricians probably enjoy digging trenches as much as anyone else.
And even if you technically can't do that, is not like you're getting array with murder, certainly building control here seem pretty pragmatic about all this! So it's not all doom and gloom

 

[ban-all-sheds]

Being honest even if you do the basics yourself eg lifting cables and digging trenches, I think that would go in your favour, as most electricians probably enjoy digging trenches as much as anyone else.

And even if you technically can't do that, is not like you're getting array with murder, certainly building control here seem pretty pragmatic about all this! So it's not all doom and gloom

Indeed, but it costs so little/nothing extra to do it properly compared to winging it that you'd have to be bonkers not to do it properly.

 

[John D v2.0]

Well, our quote for electrics in our extension was 3500+vat, so it depends what you mean by little. And I just told the building inspector I'm not doing any notifiable electrical work and so far that seems to be the end of the matter! Although completion certificate won't be coming for about 6 months id guess...

 

[ban-all-sheds]

He's using a registered 3rd-party certifier - what I meant was the OP should ask him these questions.

Edited not to cover up my mistake, but to avoid puzzling the OP.

 

[John D v2.0]

I think you're being overly cautious - yes, in theory the building inspector could be totally anal about every detail, and no doubt some are, but it makes sense to find out before hand what they're like if you stand to save thousands and know that you can do the work safely.

 

[ban-all-sheds]

Edited not to cover up my mistake, but to avoid puzzling the OP.

 

[JohnW2]

The OP claims that he told them that he wasn't doing any notifiable electrical work. That simply cannot be true - installing a CU and wiring a new house from scratch simply cannot be non-notifiable.

Unless I've missed something, it was John D, not the OP, who said that.

I cannot believe (and certainly hope not) that the OP could possible believe, let alone tell anyone, that wiring a new-build house from scratch was not (actually, in toto, given that every circuit is 'new') notifiable work.

Kind Regards, John

 

[John D v2.0]

(Edit oh yes what John w2 said)

I don't think the op claimed they are not doing notifiable work, they are just helping out the sparky that's coming in later, also the dno is only making the initial/temporary connection and not changing over to an standard install.
Maybe you're thinking of my kitchen/diner extension, which does indeed have no notifiable work in it.

 

[EFLImpudence]

Do all new houses come with EIC and Completion/Compliance certificates?

Perhaps that's why new CUs aren't notifiable.

 

[John D v2.0]

Efli, not sure if you're suggesting it or not, but you made me think maybe in the proposed install there are only 2 circuits, the sub mains, and the slave CU's could be thought of like a back of FCU's and not notifiable. However I think you might not get away with it!
Although on a related note I wonder if you would need cat IV test equipment at the slave CU's, or is it classed as safe enough for cat III?