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dan1w

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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.
 
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.
 
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.....
 
Check work BCO

You choose not to use a competent spark,..
 
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.
 
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.
 
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.
 
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.
 
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.
 
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.
 
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
 
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?
 
Wtf did i just watch pete? I couldnt decide if the hands were blue or brown it was like that dress photo all over again
 
Wtf did i just watch pete? I couldnt decide if the hands were blue or brown it was like that dress photo all over again
Agree a poor video, was trying unsuccessfully as it turns out, that perhaps the BCO was in receipt of a bribe, must try better next time.
 
Agree a poor video, was trying unsuccessfully as it turns out, that perhaps the BCO was in receipt of a bribe, must try better next time.
last 5 words of that remind me of my school reports.
 
For the OP -
As has been expressed by a few members here, we have a DIY section for those tasks we deem to be simple tasks for the home owner that we consider can be undertaken safely if certain steps are taken to ensure power is removed, the kind of things we consider would fall into this section are the changing of sockets, switches light fittings etc where you basically are changing an electrical point or accessory having said that, if through the interactions we deem the DIYer is not competent we will express our concerns and suggest they get an electrician in (safe advice is our priority).
What the DIY section or any other for that matter is not for is a step by step guide on how to do work, this applies throughout the board be you a DIY or a Qualified person.
The forum is here to help and guide but we have to be satisfied that you are competent enough to undertake the work you are doing.

Where a DIY question comes up that goes beyond what is considered DIY work then we take it on a case by case value, if the member has electrical knowledge and experience in different areas than said work he is asking about then we may be lenient and offer more advice than normal.

In this particular case of this thread in that circuits are been altered and/or extended then this should be done by a competent Electrician or you should be using a competent Electrician to oversee you work. Also to note here is said existing circuits will require to be tested prior to extending/altering them and signed off after, your average DIYer will not possess the meters to do so or the knowledge to interpret the readings, it is this fact that we limit the DIY section to simple tasks.

Lastly there are many questions that would need to be asked about the existing electrical system from circuit protection methods to bonding arrangements (if required), the incoming supply type may mean additional work is needed for a safe installation, this could include RCD protection if missing and the earthing of other services, some of these questions will not be fully understood by a DIYer and thus would require a competent person to come in and assess the job in full.
May I add, if the BCO was in deed on this job, they would be wanting the work to be fully signed off and assessed before, during and after by a competent person if the actual work itself is undertaken by the DIYer, given that you are on here asking such questions implies you have not brought a competent person in to do this as you would ask them these questions and I struggle to believe the BCO are aware the work is been done either as you would have already been told the work will require signing off by a professional.
 
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Apologies if I came off as rude as someone suggested. I just found the original few responses a tad curt, the following responses were in my opinion more reasonable and I completely understand your point of view.

In terms of the work itself, the existing circuit is up to scratch/RCD protected as new CU went in last year. the job is as it stands is not notifiable although of course BC will pull me up on anything they find that is non-compliant.

It would actually probably be worth it to remove the old cable and run new to the CU as then the onus of testing would fall to BC.

But as it stands, on completion of the garage conversion I have a sparky coming in to run a new circuit in SWA for the new detached garage, he will then test my installation, I see no requirement to have him oversee all my work.

Therefore my focus is on complying with the regs in the installation.

As to why I don't just go behind the insulation boards, although that's probably what is commonly done and also what my builder was expecting it seems that technically that would come under reference method 103 and derate the cable to 13.5A. As I'm extending the circuit, using a larger cable is not an option nor desirable.

There could be an argument that if I clip the cable to the masonry behind the insulation I could call it clipped direct, however I imagine what should be the actual derating factor for that setup is somewhere between the figures for those methods and so not so straightforward, and then there's the issue of condensation and cold bridges.

So my solution was as mentioned, reference method 102 and I just wanted clarification and how much support the cable required on the drop to the socket.
 
clipped to the brick would indeed be clipped direct as long as there was an airgap to the insulation. cable support is not a problem as you can put in as many clips as you like.
 

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