ring mains in insulated walls

[elmsoft]

The building warrant application specifies 17th edition and work done by a SELECT registered electrician.
But avoiding employing an outsider is not just to save the cost of wiring a 5 x4 metre box but all the finicky stuff of a lot of rewiring the reconfigured house.
And I have the help of a retired, time served spark.
So it goes against the grain to get involved with all the hassle of using a contractor.
I also assumed that wiring timber frame houses would be pretty common practice these days and didn't imagine building companies using anything other than 2.5 for wall sockets.

But clearly, it is back to the drawing board for me.

Thanks to everyone for their very informative input.

 

[ban-all-sheds]

The building warrant ... a SELECT registered electrician....

elmsoft

Joined: 03 Mar 2008
Posts: 109
Location: Gwynedd,
United Kingdom
Thanked: 4 times




But in any event, if you don't do what you told them you would do, and what they agreed to, what will you do at the end if they won't give you a completion certificate? (Or whatever they are called in Gwynedd, Scotland.)

And I have the help of a retired, time served spark.

Is he registered?

Will he falsely declare that he did the work?

So it goes against the grain to get involved with all the hassle of using a contractor.

Is competence not a factor when you make decisions like that?

I also assumed that wiring timber frame houses would be pretty common practice these days and didn't imagine building companies using anything other than 2.5 for wall sockets.

Hopefully the electricians involved will use the cable size which is needed.

But clearly, it is back to the drawing board for me.

It's back to using a registered electrician who will certify compliance with BS 7671 and the Building Regulations, or it's back to Building Control with a change to the application.

 

[elmsoft]

I stand rebuked and am suitably chastened.

I shall seek out a SELECT contractor forthwith

 

[EFLImpudence]

Rebuked, chastened but not enlightened.

SELECT is only in Scotland.

You need to look on the Competent Person Register.



We presume there isn't a little village in Scotland called Gwynedd.

 

[JohnW2]

SELECT is only in Scotland. ... You need to look on the Competent Person Register. ... We presume there isn't a little village in Scotland called Gwynedd.

This is getting all very confusing! - if there is such a little village, Mr Google does not seem to have heard of it!

elmsoft: Exactly where are you, and to what authority did you submit the Building Warrant application?

Kind Regards, John

 

[elmsoft]

Hi JohnWZ

I am in Scotland (Renfrewshire to be exact).
I have no idea what I did when I signed up to get the Gwynedd location!

Didn't see an obvious way to edit it either but to be honest was not that bothered.

The 17th edition is all that matters to this discussion and even if my local BO insists on a SELECT contractor I still like to know what the best method is.
Like I said, I didn't think there would be many sockets wired with 4 and 6 mm cable owing to part L - especially as these days they'll be used for low wattage table lamps.
But now I know different!
Thanks for the help and sorry for the confusion.

 

[ban-all-sheds]

For a 32A ring final the cable needs to be rated at no less than 20A.

http://www.batt.co.uk/upload/files/4d5.pdf

 

[JohnW2]

Hi JohnWZ ... I am in Scotland (Renfrewshire to be exact). ... I have no idea what I did when I signed up to get the Gwynedd location! ... Didn't see an obvious way to edit it either but to be honest was not that bothered.

Thanks for clarifying. I've never had to try, but I assume that if you click on "Profile [edit]" at the top of the page, you can change your location - we've had at least one forum member who managed to change his location on a very regular basis

... even if my local BO insists on a SELECT contractor I still like to know what the best method is.

The problem seems to be that you told them, in your application, that you would be using a SELECT contractor - so, if you want to change that, you presumably will have to negotiate with them.

Like I said, I didn't think there would be many sockets wired with 4 and 6 mm cable owing to part L - especially as these days they'll be used for low wattage table lamps.

You're right - there aren't many. Electricians generally choose a cable installation method which allows them to use 2.5mm² cable - as you've been told, if the cable is in contact with the plasterboard of the wall, then 2.5mm² is OK, even if the rest of the cable is surrounded by insulation.

Kind Regards, John

 

[AndyPRK]

So when building a new house, just how does one ensure the cables are in contact with the plasterboard ?

 

[JohnW2]

So when building a new house, just how does one ensure the cables are in contact with the plasterboard ?

I was waiting for someone to ask that - you need to ask an electrician, not me (I don't have any walls with insulation in them, and have never had to work with any)!

If the cable weren't clipped to studs and the wall were 'stuffed full' with insulation, I suppose that a cable 'in front of' the insulation would get jammed against the plasterboard when it was affixed - but that would hardly be satisfactory.

I'd be interested to know the answer, from those who do it!

Kind Regards, John

 

[sparkwright]

If we're talking about woolen fibreglass type of insulation,
if the cables weren't clipped to the studs,
rightly or wrongly
the cables would be put in place loosely,
one side of the wall would get plasterboarded,
insulation put in, pushing the cables to the back of the plasterboard,
then other side of wall gets plasterboarded.

That's what happens in the real world.

If celotex used, in most cases a void is left for air, perhaps in a ceiling or outside wall. Rightly or wrongly, often cables are clipped into position and notches made into celotex where cable in way. One of the various problems with this rubbish design is the polystyrene stuff in the celotex is likely to react with cable.

But this seems commonplace in the real world.

 

[AndyPRK]

Thanks. I suspected as much

 

[ban-all-sheds]

Celotex don't make polystyrene boards....

 

[JohnW2]

If we're talking about woolen fibreglass type of insulation, if the cables weren't clipped to the studs,
rightly or wrongly the cables would be put in place loosely, one side of the wall would get plasterboarded, insulation put in, pushing the cables to the back of the plasterboard, then other side of wall gets plasterboarded.
That's what happens in the real world.

Many thanks. That's obviously close to what I suspected when I wrote:

If the cable weren't clipped to studs and the wall were 'stuffed full' with insulation, I suppose that a cable 'in front of' the insulation would get jammed against the plasterboard when it was affixed - but that would hardly be satisfactory.

Kind Regards, John

 

[elmsoft]

But this seems commonplace in the real world.

The perfect answer to my original question. Thank you.