Conduits in insulated walls

[cjard]

What I can’t find is clear guidance as to the size of the conduit. I am assuming that the 4mm² t&e would drop down to the socket then rise again to go horizontally to the next drop – this would require two t&es in the conduit.
Or
It could it drop to the first socket then travel horizontally in conduit to the next. This would only require one t&e in the conduit.
Or
Two conduit drops per 13A socket.

To address this particular query, and these are the words from my sparky (whose opinion may differ to your sparky), once upon a time any visible electrical outlet or switching point on a wall defined a safe zone - a band of wall as wide/high as the outlet, emanating from the outlet horizontally and vertically - where wires would be run. Additionally, 150mm from every edge (where a wall/wall or wall/ceiling joint occurs) and also safe zones defined by outlets on the reverse of a partition wall apply. Wires did not abruptly change direction in a wall unless there was another safe zone that intersected with the current safe zone that the wire was being run in. Protective measures or burying to a delth greater than 50mm was required for wires not in a safe zone. The basic notion is to give ordinary house owners with limited intelligence a chance at learning some simple rules that will prevent them from banging a nail through a buried wire.

Cables don't have to be installed in safe zones where other mechanical/conductive protection from having a 50mm nail driven through them exists.


http://infinitytheforums.com/forum/topic/30773-solved-white-noise-and-smoke-questionAs such, yes you can come down a wall to socket 1, turn left and go round the entire room to the last socket and then head up to the ceiling, or directly through a partition wall if there's an outlet on the other side

The spirit of other posts here is eminently sensible - choose an electrician, get him on site for an hour or two, pay him for his time and ask him a string of questions centred around "how should I construct the rest of my house to make your life easier?"

 

[EFLImpudence]

and also safe zones defined by outlets on the reverse of a partition wall apply.

That's not really the case.
This is an instant where the 'safe zones' would better be described as 'danger zones'.
That is - in a partition wall upto 100mm. thick an accessory on the other side indicates where the cable is or may be installed on your side.
It does not mean you may run unrelated cables on your side. In any case a 'safe zone' is only created for the cables connected to that accessory.

As such, yes you can come down a wall to socket 1, turn left and go round the entire room to the last socket and then head up to the ceiling, or directly through a partition wall if there's an outlet on the other side

You can go horizontally around a room but there must be an accessory connected on each wall.

//www.diynot.com/wiki/Electrics:walls

 

[charliegolf]

From BAS:

Somebody is going to have to sign this:

I being the person responsible for the design, construction, inspection & testing of the electrical installation (as indicated by my signature below), particulars of which are described above, having exercised reasonable skill and care when carrying out the design, construction, inspection & testing hereby CERTIFY that the said work for which I have been responsible is to the best of my knowledge and belief in accordance with BS 7671:2008, amended to 2015 except for the departures, if any, detailed as follows:

I found this very interesting to read (having read lots of posts about 'signing off' electrical work, but never seeing this in the flesh). Now I'm a very good reader, very good at following instructions; and easily capable of tracking down a copy of BS7671:2008 amended to 2015. Why can't I do such work? (I need a feed to my stable!) I'm also a good law abiding person, so I won't. I assume there's a register?

CG

 

[EFLImpudence]

I found this very interesting to read (having read lots of posts about 'signing off' electrical work, but never seeing this in the flesh). Now I'm a very good reader, very good at following instructions; and easily capable of tracking down a copy of BS7671:2008 amended to 2015.

It's 496 pages - not all relevant, obviously.

Why can't I do such work?

You may do the work - after notifying the Local Authority (legal requirement and hefty fee) and getting their approval or employing a registered electrician in which case aren't we back to square one?

The problem is if you can't do the work; i.e. don't have the knowledge, equipment etc.

 

[ban-all-sheds]

Ban-all-sheds:

Whilst I applaud your desire to make sure that I get this installation right and within the appropriate regulations I can’t understand why you should viciously berate the person that you call a “useless incompetent t**t.”

Everything a project manager does is supposed to avoid situations like this arising. He's failed in his basic task of scheduling things for the right time and in the right sequence. It seriously p***es me off to see people who are supposed to be competent professionals, and who are taking money to act as competent professionals, being so incompetent and unprofessional.

You have assumed that this project will not be designed and signed off by a competent person – you can’t know that.

I can know that because I know that you have come to a website to ask random strangers who cannot sign it off to do the design.

You can only incorrectly infer it from what I have written.

It's not an incorrect inference - you were asking for people here to do the design for you:

What I can’t find is clear guidance as to the size of the conduit. I am assuming that the 4mm² t&e would drop down to the socket then rise again to go horizontally to the next drop – this would require two t&es in the conduit.

Or

It could it drop to the first socket then travel horizontally in conduit to the next. This would only require one t&e in the conduit.

Or

Two conduit drops per 13A socket.


Is there another way?

Would it be appropriate to apply the 45% rule as the conduit would be embedded in insulation?

You would be advised to ask questions before jumping to conclusions. And if you think I am stupid enough to complete a project without the right certifications then you are wide of the mark.

So who do you plan to have sign a declaration to certify that they did the design which was done for you by random strangers on the Internet?

I have full contact with BC and with LABC who are guaranteeing the build.

So when you applied for Building Regulations approval you told them that as part of the way you'd ensure compliance with Part P you'd be asking random strangers on the Internet to carry out aspects of the design? Interesting.

As a retired Civil Engineer with a further, albeit minor, qualification in electrical engineering I could design this installation

Were that so you would not have needed to ask people here to tell you what size conduit to use.

but I am not qualified to sign it off. What are your qualifications?

Irrelevant, as I'm not designing and certifying this.

For reasons that I will not bore you with I simply need to install a few lengths of conduit in advance of the final design and installation of the system.

That IS design and installation.

I have jumped to the conclusion that you had had a bad day or as the time of the post was late Saturday night you were probably just the worse for drink.

You would be advised to ask questions before jumping to conclusions.

I have as much justification for that view as you had for yours.

If my view is unjustified, just what is the reason that the project manager has allowed the project to get to the stage where electrical installation design and construction is needed but nobody suitable has been engaged to do it?

You have no duty of care to me.

I disagree.

Please be aware that I will not respond to any further posts from you, Ban-all-sheds

Well, I hope I've answered all of the outstanding questions you raised, and addressed all of the points you made in your post of 00:45.

 

[SimonH2]

Why can't I do such work?

You can. There are very few restrictions on who may do electrical work - which is good news for those of us into DIY and with the skills to do it. The biggest question is whether you are "competent" to do the work - the law does not require any qualifications, only that you be competent which is a different thing altogether (you have to question whether some qualified people are competent ).

(I need a feed to my stable!) I'm also a good law abiding person, so I won't.

That is likely to count as a new circuit, hence is notifiable. If you were to (for example) just spur off an existing ring final and put a socket (and perhaps a fused connection unit for lights) at the other end then that wouldn't even be notifiable. If you added a new MCB in the CU, and a small CU at the other end then that would be notifiable (both because it's a new circuit, and because it's installation of a CU).

I assume there's a register?

No, there's no register as such. An installation certificate should be given to the person procuring the work/building owner on completion of the electrical work. It is up to them to keep this piece of paper safe and in practice the only time it's likely to be needed is either :

• When some box-ticking solicitor wants it during a (house) purchase
• Or "something happens" that causes an investigation and one of the things that gets looked at is "who did the electrics" involved.

IF the work is notifiable (and not done by a member of a registration scheme) then it will (or should !) appear in the files of Building Control Notices at the local council, otherwise they will probably know nothing about it.
IF the work is done by a member of a registration scheme, then it'll appear in a list of work kept by the scheme.
So multiple registers, and the work may appear in one of them - or it may appear in none of them.

EDIT: What is rather annoying for some of us is the level of fees charged by LABC departments. Mine is apparently at the cheap end, but still charge a minimum of £150 for electrical works - or 50% more if they are going to have to get an electrician in to do tests.
Needless to say, when I replace the CU, I'll be putting in stub circuits for everything I think I might need in the future

 

[stillp]

Mine is apparently at the cheap end, but still charge a minimum of £150 for electrical works - or 50% more if they are going to have to get an electrician in to do tests.

How much testing does the electrician do for the £75? Sounds pretty cheap to me!

 

[SimonH2]

You have no duty of care to me.

I disagree.

And in this case I do believe you are not correct.
While I realise Wikipedia isn't a 100% accurate body of knowledge, there's a very interesting page on Duty of Care, and a section on omissions. https://en.wikipedia.org/wiki/Duty_of_care_in_English_law#Duty_of_care_for_omissions
Generally, no duty of care may arise in relation to pure omissions; acts which if taken would minimise or prevent harm to another individual
So no, BAS does not owe jamesph a duty of care.

But, I too would feel that it would be my duty to point out if someone is planning to embark on something potentially dangerous. But, that doesn't extend to being anally retentive or abusive about it.

 

[SimonH2]

How much testing does the electrician do for the £75? Sounds pretty cheap to me!

I assume the basics of an EICR.
For a CU replacement I suppose it's not bad, but for more minor works it gets more significant.
For larger works, I assume they invoke the "% of project costs" method of charging.

 

[EFLImpudence]

You can.

No, he may do it; we don't know if he can.

There are very few restrictions on who may do electrical work - which is good news for those of us into DIY and with the skills to do it.

Precisely.

The biggest question is whether you are "competent" to do the work - the law does not require any qualifications, only that you be competent which is a different thing altogether

So, perhaps he can't.

 

[charliegolf]

Prior to the law changes about notifiable work, I did wire up 4 double sockets, a single for the door mechanism, and a light fitting, for the garage I built (mainly myself). I ran swa underground to the garage (5m ish), and connected each end to a cu. Since the changes, I have swapped light fittings, and changed faceplates on sockets. I understand all of these recent jobs are legal? As for Simon's remark...

"If you were to (for example) just spur off an existing ring final and put a socket (and perhaps a fused connection unit for lights) at the other end then that wouldn't even be notifiable."

I thought anything TO an outside building WAS notifiable. No?

CG

 

[EFLImpudence]

It still is in Wales. There's devolution for you.

 

[SimonH2]

No, he may do it; we don't know if he can.

I stand corrected, silly of me

I thought anything TO an outside building WAS notifiable. No?

It was, but now it isn't.
The rules were very significantly relaxed in (IIRC) 2013, and now the only notifiable works are :

• Replacing or installing a CU
• Adding a circuit
• Work within the zones of a bathroom

So spurring off a ring final and adding a socket in the shed isn't notifiable, but if you add an MCB in the CU then it is. You still have to comply with Part P - but basically that means complying with BS7671.

EDIT: That's for England only.

 

[ban-all-sheds]

You have no duty of care to me.

I disagree.

And in this case I do believe you are not correct.
While I realise Wikipedia isn't a 100% accurate body of knowledge, there's a very interesting page on Duty of Care, and a section on omissions. https://en.wikipedia.org/wiki/Duty_of_care_in_English_law#Duty_of_care_for_omissions
Generally, no duty of care may arise in relation to pure omissions; acts which if taken would minimise or prevent harm to another individual
So no, BAS does not owe jamesph a duty of care.

I disagree.

Probably because I have higher standards of honesty, truthfulness and morality than most people here are willing to allow to exist without continually attacking them, which (again probably) they do because they do not like to be shown to be lacking in those areas.

I don't give a toss about what the law says I may debase my standards to - I know what is right.

But, I too would feel that it would be my duty to point out if someone is planning to embark on something potentially dangerous. But, that doesn't extend to being anally retentive or abusive about it.

The only person I've "abused" here is the anonymous con-man who is taking the OP for a ride by pretending to be a competent and professional project manager.

 

[jamesph]

Hello All,

This is a complete waste of time and energy – most of which is way off the OP

I am done with this thread.

Thanks to all who took the trouble to address the question some of which was helpful.

Regards to all.