Electrical Advice - New Consumer Unit

ahll

Hi all
Getting a new kitchen fitted soon and changing from a gas cooker to a seperate electric oven and hob. The existing Consumer unit is an old one that uses BS3036 fuses (wired ones).

I am wondering if there is a good reason to updated the consumer unit ? If so can anyone recommend a good valued one that will comply with the 17th Ed for a standard sized terrace house with lights, sockets, Shower so nothing unusual.

Also what is the best way to connect an oven and hob if they both have to be hardwired ? Is there any reason you cant run cable to a Cooker Switch and then to a 63Amp juntion box then run two wires from there, one to the cooker and one to the hob ?

AdrianW2

Building control won't sign off a new circuit on the old fusebox, so you'll need a new one.

There are some comments on consumer unit quality and price on the "ensure your electrics" thread.

ahll

I didnt realise Building Control wont sign off a new circuit on the old fusebox ! I didnt think there would be a problem as long as it was electrically safe eg right sized cable, mcb....

Has anyone had this problem ?

AdrianW2 wrote: »

Building control won't sign off a new circuit on the old fusebox, so you'll need a new one.

There are some comments on consumer unit quality and price on the "ensure your electrics" thread.

zax47

Two issues here regarding new/amended kitchen circuits and LABC (Local Authority Building Control) sign-off. Firstly the work must be done by a "competent person" (i.e. qualified/certified/registered) to BS7671:2008 17th Edition wiring regs and secondly, all new circuits in special locations (kitchens, bathrooms, outside) under the 17th edition of BS7671:2008 must be RCD protected.

No-one can force you to upgrade the old fused CU if you don't change/add any new circuits to it, but any NEW circuits must meet current regs!

However, if I were doing this job (I am an electrician) and you desperately didn't want a new CU fitting then I'd split the meter tails into a pair of Henleys, fit a new 4 way CU with RCD protection and run a dedicated radial circuit (with it's own MCB) for the kitchen sockets, another for the oven and a third for the hob. It is unwise to put hob and oven on the same radial circuit due to their potentially high individual current loading.

zax47

AdrianW2 wrote: »

Seems to me that there's a gap in the market for a plug-in RCBO for old Wylex boxes.

The extra connections required (to earth & neutral) would be the reason these don't exist. It wouldn't be practical (or safe) to get a DIYer (however competent) to make them, as it would entail going deep into the CU.

EDIT: Hey - where did that post I quoted go??

AdrianW2

zax47 wrote: »

EDIT: Hey - where did that post I quoted go??

I deleted it when I realised why it wouldn't work!

Cknocker

If you decide to go for a new CU, B&Q currently have 10way Twin RCD MK 17th edition boards, fully loaded with a variety of MCBs for £80. I would be surprised if you can get a MK unit that price anywhere, could one of the electrians here confirm?

PS don't try fitting it yourself!!!!!

ahll

I am not saying I wont get the CU changed I just wanted to see what my options are.

If I do what you sugesting below wouldn't I then need to have 2 separate Cooker Swtiches - One for the cooker and one for the hob ?

Previously I have not had any poblems with a cooker and hob being on the same circuit.

What do you mean when you say 'I'd split the meter tails into a pair of Henleys' ?

zax47 wrote: »

However, if I were doing this job (I am an electrician) and you desperately didn't want a new CU fitting then I'd split the meter tails into a pair of Henleys, fit a new 4 way CU with RCD protection and run a dedicated radial circuit (with it's own MCB) for the kitchen sockets, another for the oven and a third for the hob. It is unwise to put hob and oven on the same radial circuit due to their potentially high individual current loading.

zax47

ahll wrote: »

What do you mean when you say 'I'd split the meter tails into a pair of Henleys' ?

Sorry - electrician speak, not for DIYers! You MUST have a professional electrician to do this work - it is ALL notifiable work under Part P of the Building Regulations. With all due respect, the questions you are asking are exactly why it needs a pro. An electric hob (of any type) can easily require more than 30A on its own! Stick that on a circuit with an oven needing 15A and suddenly a 40A isolator ("cooker switch") isn't enough.

baldelectrician

I won't ralk about Part P here- different issue

It is more important to have the job done right. There may be a strong likelihood for two circuits (oven and hob) as they will probably be of a higher total rating

You should use a competent person for the work, links below
In Scotland:
Individuals registered;
http://www.sbsa.gov.uk/register/ListAC.asp
Companies
http://www.sbsa.gov.uk/register/Sear...struction&ID=2
In England and Wales:
http://www.competentperson.co.uk

ahll

Then a 45A can be used. If you had a free standing cooker, that has an oven and hob just there not seperate and it would have to be on the same circuit and that would be ok wouldn't it ? So whats the difference just because they are seperate ?

zax47 wrote: »

Sorry - electrician speak, not for DIYers! You MUST have a professional electrician to do this work - it is ALL notifiable work under Part P of the Building Regulations. With all due respect, the questions you are asking are exactly why it needs a pro. An electric hob (of any type) can easily require more than 30A on its own! Stick that on a circuit with an oven needing 15A and suddenly a 40A isolator ("cooker switch") isn't enough.