kitchen rewire

[richard633]

hi - I'm a new poster here so bear with me....!

I'm fitting a new kitchen and (as I see many here discover), there is a lot of wiring to sort out first and this becomes involved...

Basically the kitchen used to have one of those cooker supplies high on the wall ,which has been since been removed, but the 4mm wiring ( which looks recent) extended to serve 4 TSOs as well as an oven and a light.

I intend to reinstate this 32A supply ( 4mm I think it is) as purely for my double oven. I will then install a whole new ring main in 2.5mm connected back to the fuse box ( old type without RCD ) to serve most of the kitchen. ( but not dishwasher or washing machines - I haven't investigated those) The new ring will run down the gable end of the house in plastic conduit.

I plan to do most of this work myself, calling in a sparks to certify.

My question is - is this a reasonable plan and if so do I need to replace the fuse box? It looks about 25yrs old with mostly old fashioned fuses but with a couple of Wilex (?) MCBs added in by someone. There is just one spare position available for my new kitchen ring main.

Thanks in advance

Richard

 

[riveralt]

I plan to do most of this work myself, calling in a sparks to certify.

Splendid but you will either need to speak to you Local Authority Building Control first - to inform them of the work you intend to do - and pay there fee. Or you need to speak to the electrician first because a registered electriician cannot certify any work other than his/her own.

 

[EngStudent]

Firstly, you'll need to get a sparky in before you start work. That way you can agree with him what you're doing and what he's doing.

Secondly, unless he sees the route of this 4mm cable, he might not be willing to put his signature to any work. This light that it supplies; is it the main ceiling light?

Finally, the circuit for the oven and the ring final will have to be covered by an RCD. You can achieve this by either a) splitting the tails and having a second CU installed for these circuits, or b) install a new CU for all circuits in the house. This would mean the rest of the circuits having to be tested and any neccessary remedial work carried out. Both options will almost certainly require an upgrade of water/gas/oil bonding.

 

[cumbriahandyman]

I plan to do most of this work myself, calling in a sparks to certify.

Splendid but you will either need to speak to you Local Authority Building Control first - to inform them of the work you intend to do - and pay there fee. Or you need to speak to the electrician first because a registered electriician cannot certify any work other than his/her own.

Not actually true, but you will need to speak to the certifying spark who will tell you what he is prepared to let you do.

 

[riveralt]

I plan to do most of this work myself, calling in a sparks to certify.

Splendid but you will either need to speak to you Local Authority Building Control first - to inform them of the work you intend to do - and pay there fee. Or you need to speak to the electrician first because a registered electriician cannot certify any work other than his/her own.

Not actually true, but you will need to speak to the certifying spark who will tell you what he is prepared to let you do.

Sorry which part is not true?

 

[ban-all-sheds]

there is a lot of wiring to sort out first and this becomes involved...

Probably more involved than you realise, so you should probably invest some time in learning how to design and install circuits rather than just diving in.

I intend to reinstate this 32A supply ( 4mm I think it is) as purely for my double oven.

You must not use a 4mm² cable on a 30A rewirable fuse, and you might not be able to use it on a 32A MCB - it depends how it's been installed.

I will then install a whole new ring main in 2.5mm connected back to the fuse box ( old type without RCD ) to serve most of the kitchen.

1) NO -you need an RCD.

2) Is a ring final the most appropriate type of circuit here, or would a radial be better?

I plan to do most of this work myself, calling in a sparks to certify.

1) It doesn't work like that: //www.diynot.com/wiki/electrics:part-p

2) I don't think you know enough to be sure you won't screw up.

My question is - is this a reasonable plan and if so do I need to replace the fuse box?

You are not compelled to replace it per se.

New circuits, sockets added to new circuits, new light switch drops will almost certainly mean you need to add RCD protection, and you'd be strongly advised to have that on existing sockets anyway.

A 2nd CU for new and changed circuits would be the easiest way to sort out the RCD requirement, so you might as well just have the existing one replaced.

Replacing a CU is also notifiable, it requires testing, and it's strongly advised to carry out some testing before starting the replacement.

On balance you should get an electrician.

 

[richard633]

Ok - looks like I was about to fall into some well known traps so thanks for the advice.

I'm not an electrician by any means but I would enjoy reading up on this and doing my own installation. Possibly I am being over-ambitious given that a new RCB consumer unit is probably required with the knock on effects of that.

If I do go down the building control route, how do building control do the necessary testing? Presumably they would put the onus on me to do that so I would need to employ someone .

Anyone know a good book on this that's at about the right level?

 

[EngStudent]

If I do go down the building control route, how do building control do the necessary testing? Presumably they would put the onus on me to do that so I would need to employ someone .

Anyone know a good book on this that's at about the right level?

Building Control would sub-contract an electrician to inspect at first-fix and then I&T at second fix. This should be part of the fee (I'm sure BAS will be along with more information with regards councils that don't do this).

'Basic Electrical Installation Work' by Trevor Linsley was always used when I was at college. You'll also want a copy of the On-Site Guide and possibly BS7671:2008.

 

[Taylortwocities]

Reading up on it is one thing.
Putting it all into practise so that it complies with Building Regulations Part P and (by extension) BS7671 is quite another.

Changing a consumer unit is basically a heart & lung operation on your electrical installation and you will need some expensive, calibrated test equipment so that you will be able to complete the 6-page Installation Certificate.

View one here http://www.planningportal.gov.uk/uploads/br/BR_PDF_ADP_2006.pdf
Appendix B

You would be much better getting together with a friendly local REGISTERED electrician and work with him. You'll learn lots and he will look after all of the nasty legal paperwork...

Get a local one at www.competentperson.co.uk

 

[ban-all-sheds]

Mmmm ... well .....

As ever, personal recommendations are always the best way to find a reputable tradesman, but if you're having to go ahead without much in the way of those, or references, don't put any store by registration itself - sadly it is possible to become registered with woefully inadequate qualifications and zero practical experience. You don't have to spend long here to see people cropping up who are registered and "qualified", but who are clearly seriously incompetent in reality and who should not be charging for their services.

You are looking for someone to replace a CU, and it may surprise and dismay you to learn that it is quite possible to become a "certified electrician" without ever having done that before, and without having acquired any of the practical skills needed to do it without half-destroying your house in the process.

It's your money, and you have every right to ask prospective tradesmen what their qualifications and experience are. Just being listed here is not a good enough guide. No genuinely experienced electrician, with the "full set" of C&G qualifications will mind you asking - in fact he will wish that everyone was like you.

I feel sorry for people who have been misled by training organisations and (shamefully) the Competent Person scheme organisers into thinking that a 5-day training course, a couple of trivial examples of their work and some basic understanding of how to use test equipment will make them an electrician, but not sorry enough to agree with them trying to sell their services to Joe Public.

 

[richard633]

update -

I managed to get a friendly local electrician (who was recommended) round to have a look last night. He quickly understood the issues and seemed happy for me to go ahead with the basic installation myself inc the new earth etc. I'll do some reading up before pressing on though. He had some comments on what I had done already but the basic plan was good and the problems easily rectified.

He will inspect what i've done before plastering and fit the 'fronts' and the new CU. I'll get all the hardware from Screwfix.

I anticipate other problems coming to light once the new cu goes in and is tested because the rewire in the '80s seems amateurish, even to me, but we'll see what happens.

All in all I feel very positive about the outcome which seems common sense - so thanks to all here.

Richard

 

[riveralt]

update -

I managed to get a friendly local electrician (who was recommended) round to have a look last night.

Just make sure he is registered will one of the competent persons scheme otherwise you and/or he will have to go through the LA BC.

He quickly understood the issues and seemed happy for me to go ahead with the basic installation myself inc the new earth etc. I'll do some reading up before pressing on though.

What size cable did he tell to install? What type of Earthing System do you have? What is the current Ze value?

He had some comments on what I had done already but the basic plan was good

Not the plan you outlined in your first post I hope?

I anticipate other problems coming to light once the new cu goes in and is tested because the rewire in the '80s seems amateurish, even to me, but we'll see what happens.

Is this guy really an electrician - because what is the point of fitting a CU without testing the circuits to identify the 'problems' before hand. This IS an 80's amateur approach.

All in all I feel very positive about the outcome which seems common sense - so thanks to all here.

Given what you have said so far you may not feel that confident afterwards.

Personally I would get three separate quotes and advice for the work you propose.