Need Advice - New Kitchen Rewire

[Stephen Paul Jones]

Hi Guys
New to forum and enjoying reading the threads, all interesting, so..
Looking to re-wire my kitchen due to re-fit and some of you will be unhappy (understandibly) as I am not a qualified sparky, but I will notify building control and get the work certified and passed. This is simply an interest of mine and I enjoy it, I certainly don't intend killing myself or anyone else in the process and will get in local authorities for cert...so here goes, lot's of reading, bear with me, as I really can do with the help to clarify if I am wrong alltogether or on the right track being a diy'er.

I am now installing at home a built in oven 3.39kW, microwave 900w, induction hob 7.5kW, Fridgefreezer, under counter freezer, washing machine and Cooker hood 250w.

All appliances with 4 meters of DB and Clipped direct to wall behind open cavity, not insulated, 75mm cavity to address 50mm depth regs, don't intend to mechanically protect wiring, due to 75mm deep and RCD protected. Walls plasterboard lined for convenience, all wiring within prescribed zones!

So, would this be correct for regs... I have a
Wylex,14way Split Load DB, 2x 80A/30ma RCD's with the addition of potential seperated RCBO's below:

Oven and Induction Hob - DB 32A RCBO
Appliance's Total = 10.89kW- 47.34A using diversity and if maths correct:-
30% = 11.2A, 11.2A+10A= 21.2A total, so from DB using 6mm cable via 45A CCU down to Dual Cooker Outlet using 6mm cable, seperated and terminated at both appliance's using 6mm cable.

Fridgefreezer and Freezer - on separate 20A RCBO dedicated radials using 2.5mm cable via Switched FCU's down to flex outlet plates.

Washing Machine - I'm sure read somewhere regarding Nusiance tripping, not sure if 17th Edition about putting the likes of the washing machine again, on a dedicated curcuit, 20A RCBO using the usual method mentioned or, I could spur off rfc with Switched FCU down to flex outlet plate. This was when I was told I was over the top and pointless by a Sparky, always learning, even at 50.

Finally Microwave(900watt) and Hood(250watt) total 5A
Could these both appliances be powered via a junction box to separate FCU's and outlet plates, on 10A RCBO dedicated radial curcuit.

I have room for these dedicated radials and can keep the RCD protected Split Loads seperate, would this then be the making of a High Integrity Unit?
DP RCBO's or SP RCBO's, so many views on this, not sure.

If you have read this far, I commend you for your patients and appologise if my terminology is not adequate and certainly look forward to your comments and would really appreciate the feedback.

 

[Barnaby Stedman]

Do you realise the difference between a DP RCBO and a SP RCBO?

 

[Pete999]

may have this wrong, but you mention you are fitting a dual RCD CU WITH 2 X 80Amp RCDs why are you intending fitting RCBOs, there will be no need as your outgoing circuits will be RCD protected by the 2x RCD s in the CU?

 

[rolyberkin]

Without sounding negative how are you going to test all of this? It's all very well putting cables into sockets and clipping them to the wall but if you aren't going to test it properly and actually understand the results of the tests getting LABC to sign it off won't mean a thing. Also an electrical certificate requires three signatures, one for design, one for installation and one for inspection and testing, how will this happen? How will you know if it is safe prior to flicking the switch?

 

[Dustydazzler]

Without sounding negative how are you going to test all of this? It's all very well putting cables into sockets and clipping them to the wall but if you aren't going to test it properly and actually understand the results of the tests getting LABC to sign it off won't mean a thing. Also an electrical certificate requires three signatures, one for design, one for installation and one for inspection and testing, how will this happen? How will you know if it is safe prior to flicking the switch?

Bang Test ?

 

[Wilko]

Hi - Like any learner, you should not attempt hazardous tasks for which you’ve not been trained. Maybe a find a friendly local Electrician to work with?

 

[Nelder]

I'm sorry but its clear you don't fully know what your doing. There can be no doubt when electricity is involved.

 

[Stephen Paul Jones]

Yes, agree totally with all comments. Wilko, I will get a local electrician to work with and for the reasons Rolybarkin mentioned. Pets 999, I think I will replace with a full board of RCBO's, understand what you are saying, RCD's are already in situ and thought it would be a better arrangement if some curcuits like the freezer are separated from the bank of RCD protected curcuits. Less chance of tripping by isolating those curcuits, especially when you have a fridgefreezer full of grub. apprciating the comments...

 

[remedial]

for the oven I'd put in a 10mm cable for future proofing.

all the separate radials are overkill. if isolation is needed thats what the FCUs are there for.

 

[Stephen Paul Jones]

I thought that.. now you have mentioned it, I will. cheers Remedial. I agree overkill perhaps, but I think it will be cautious and good practise from a design layout to have at least the fridgefreezer and has I have with the garage on their own separate RCBO curcuits, preference I suppose. Thanks Guys

 

[Intoelectrics]

There's nothing wrong with discrimination in any electrical design, usually more the better. But there is no need to over kill it, which would be costly for no particular good reason. Individual RCBO's are a preferred method and much better for kitchen installations where there is the likelihood of many different electrical appliances being used.
Much more sensible to get a local electrician in to design the install for you, maybe be ok with you working on it and then the sparky signing it off after completion.
Testing of these systems is a requirement and requires the correct testing equipment, knowledge and understanding to complete competently.
If you proceed on your own you could find you have made a costly mistake when its too late. Better to learn as you go with the assistance of a knowledgeable and experienced time served qualified professional.

 

[Midwest]

What about SPD's & AFDD's?

 

[Stephen Paul Jones]

I have mentioned SPD's to some sparky's locally and I see the sense of them with the amount of electronics within households today, but one sparky told me SPD's are a pain in the ar** to install due to the complicated risk assessment paperwork involved, but reading the regs as a DIyer that I am, this is now compulsory on a single dwelling if you do not complete a risk assessment, am I correct Midwest.

 

[Octopus]

but reading the regs as a DIyer that I am, this is now compulsory on a single dwelling if you do not complete a risk assessment, am I correct Midwest.

No.

 

[Stephen Paul Jones]

Intoelectrics... agree, I'm not a sparky, but feel that RCBO's can fit into design alongside RCD protected circuits for discrimination as you stated, especially the kitchen. Also agree with calling in an electrician to assess my install and signing off before energising system. Doing this for the enjoyment and knowledge...but safety is paramount!