Wiring in insulated stud wall

[dan1w]

Hi,

I hope someone will be kind enough to assist me.

I'm wiring my garage conversion(extending an existing radial). The walls are skinned with 70mm studwork and 50mm rigid insulation leaving clearance of 20mm. The builder wants to maintain an air gap at the rear reducing clearance further.

I understand to avoid excessively derating the cable it is best to run it touching the plasterboard on the inside.

Given the clearance I have is it acceptable to run the cable in safe zones away from the studs using notches in the noggins as support and to keep the cable touching the plasterboard? If so do the the noggins have to be a minimum distance apart? Is there a better way?

Any input much appreciated and just to note this will be inspected by a BCO.

 

[Octopus]

If BCO are inspecting, then best you ask them......

 

[dan1w]

I spoke to the BCO yesterday and we agreed that it would run touching the plasterboard and had to be clipped.

I thought okay fine then it just occurred to me this evening that I only have room to clip one cable to the stud and would have to dismantle and install additional studwork just to clip the other cable coming from the socket.

One side of the room has to be wired and photographed on Sunday before the boards go over it on Monday morning so I won't get to clarify with BC before it's boarded.

 

[Octopus]

Tough.

 

[dan1w]

I think the regs say vertical runs in 2.5mm need to be clipped every 400mm but then you see tons of examples of people stitching cables into existing studwalls and notching the noggins so.....

 

[Octopus]

Check work BCO

You choose not to use a competent spark,..

 

[dan1w]

Exactly what is the purpose of the DIY section of this forum?

 

[Wilko]

Hi - I guess advice given here (on this topic) could be misinterpreted or half followed and unknowingly you will have created a hidden risk. Some other things are more straightforward diy tasks.

 

[uksrevivor]

May i suggest that before the "Radial" is extended it is tested to ensure that it will be sufficient to take the new load you intend to place on it.
And BCO are not electricians. The purpose of the DIY section is to try and advise people of basic jobs and this is a bit more than basic.

 

[Bubba sparks]

It’s good that you’ve given it thought, I’m sure many diy folks wouldn’t. If you’re within safe zones and your cables are adequately supported then I can’t see a problem there. I wouldn’t be getting my tape out to measure clips but I would walk away knowing my cables were going to stay where they need to. Ultimately though, Is it not the person who will be testing & certifying this work that needs to be happy rather than the BCO? Surely his main concern is that you have a certificate.

 

[Pete999]

Exactly what is the purpose of the DIY section of this forum?

I would the the purpose of the DIY section is to advise non Electrical people DIYers as well, on whats the best way to get work done etc, Not to give people step by step instructions on how to do installations that should be carried out by competent Electricians, with the right experience, knowledge and equipment so as not to injure themselves or anyone else for that matter.

 

[Octopus]

Exactly what is the purpose of the DIY section of this forum?

To assist with minor issues ............. a garage conversion, being tested by BCO is not minor............... you must have convinced them that you have some competence.

And every garage conversion I've been paid to work on has involved changes to the lighting circuit too.

 

[telectrix]

reading the OP', original post, I'm at a loss as to why he does not install the cable in the airspace behind the insulation.

 

[Pete999]

To assist with minor issues ............. a garage conversion, being tested by BCO is not minor............... you must have convinced them that you have some competence.

And every garage conversion I've been paid to work on has involved changes to the lighting circuit too.

The OP could have been making these to give to the BCO

 

[Midwest]

I have the feeling the OP will not be back, could be wrong. I often wonder what that greyed out text is about before you type a reply 'Write your reply here.... Make sure your reply is in-keeping with the forum rules, polite and professional. If you disagree with the post(s) above, you can still be professional with your reply'.

Anyway, there's 70mm of timber to clip the cables?