mcb and cable size help

[Rattled]

Hello all

I've just developed a wiring fault on the only ring main, after spending a few days attempting to find it and being pretty appalled by my findings. I have decided to re-wire the house. I have just spent all my spare money on a cruise so I guess I will have to get "Me sen ltd" to do it all, this is not really my forte being an industrial electrician; I have never re-wired an house. so the first issue I have is cooker cable and mcb size, I have no Idea what kw rating the as yet unknown cooker will be and what kw rating I should base my calculations on, is there a rule of thumb? I currently have a 8 ring range, duel fuel, gas hob and electric ovens, this will certainly be replaced as part of the consequence of the re-wire as it's crap and i'll be building a new kitchen after I wreck the old one.

 

[Barnaby Stedman]

normally a cooker switch is on a 40a mcb - however it all depends on the cooker rating
but you better make sure you know what you are doing before you go too far
best of luck - i admire u for taking on the challenge of a rewire - but get it checked and tested by a proffesional and make sure it is up to part p and BS 7671

 

[buzzlightyear]

based on your finding that you said and will rewire your self ,by going down that path ,it would be advisable to get a spark to work with you .
but saying that the spark could do a third party testing ,where you put the cables in and he tests it ,for part p .

 

[Deleted member 26818]

A lot of cookers now can be connected using a 3 pin plug.
That being said, I would probably install either 6mm2 or 10mm2 cable, then size the MCB/RCBO according to the cooker load (once known).

 

[Rattled]

https://www.NoLinkingToThis/p/briti...d-high-integrity-dual-rcd-consumer-unit/3150g looking at starting with this I will go for a 10mm2 cable I think, just to be on the safe side that gives me a 10kw max capacity oven for the length of the run.

 

[richy3333]

And installation method, voltage drop etc

 

[Rattled]

The calculator said Enclosed in conduit in thermally insulated wall that is the closest I can find. A guy I know from the pub is part P he will come around and test when I'm done, he did this for the Kitchen ring I put in my rental property.

 

[telectrix]

if the cable is buried in masonry/plaster, it's ref. method C...clipped direct.

 

[Rattled]

It will be under floorboards and plaster so clipped direct means I only need 6mm2 for a 10kw oven with the 12m run. thanks for all the help

 

[buzzlightyear]

A guy I know from the pub is part P

is his name Mr bodge and scarper by any chance , I had him once never again.

 

[Rattled]

I admit I am not any good at house wiring but I trust my testing with my life daily and I can reed my on site guide so, If he will sign and write his name on the paperwork I have everything I need in court for an insurance claim. I can't see how I will get an oven over 5kw so 6mm2 it is.

 

[The Ghost]

Two points. One, third party testing requires the person to be in at design stage and test as the installation goes in. I am third party accredited and know if I do third party I have to be in at design of circuits and test cables as they are installed. If not then I can not issue a certificate.
Two, when designing we are to design not just for the immediate needs of the client but also the future possibilities. So if someone decides to put a 18kw range cooker in the kitchen in the future thought should be given to this. Therefore a 10mm supply at 40a MCB allows future flexibility. Terminated to a cooker switch with a socket outlet covers for quite a lot of things?
Finally it is with interest I note, not for the first time, that a "real electrician" as it is viewed on here by many is having some misgivings about one of the most ridiculed and lowest of the low electrical work. Populated exlusively by five week wonders as the derogatory description is oft used.
It seems then there is a skill set that is not necessarily so easily covered as a "real electrician" and that maybe just maybe you and others who have asked the same question may take time to pause and consider that there is a little bit more to domestic than the usual pillorying and jaundiced view.
This is not aimed at you personally so don't take it that way. It's just striking a blow for a more balanced view of a domestic electrician and giving credit where credit is due.