Advice please regarding cooker circuits

[TonyH1208]

Hi Everyone,

My name is Tony and I've just registered.

I've spent 30 years in the computing industry installing large mainframes etc. I know my way around electrical circuits and theory but have no formal qualifications.

I have a question.

I'm having a new kitchen fitted shortly and having installed a single oven rated at 3.6Kw and a microwave rated at 3.6Kw also. My existing kitchen has a double oven which is fed by a 30A cartridge fuse via 4mm cable to the cooker isolation switch in the kitchen. The total distance is around 10-12 metres.

Looking at the power rating for this circuit, I think it should run at 7.2Kw which is the total of my two new appliances. However, I'm a little loath to run any circuit to its maximum capacity in case the circuit trips or, worse, becomes a fire risk.

I'm looking at running a 6mm cable from my existing consumer unit to an additional 2 to 5 way consumer unit directly above the kitchen in the eaves. The original Wylex CU would have the fuse rating upgraded to a 40A MCB and the new consumer unit would have two separate circuits each rated at 30A to each individual appliance.

Is this the best way to do it, or would the existing circuit be sufficient anyway?

Although I will be doing the work myself, I intend to get a professional electrician in to certify the installation afterwards.

Many thanks,

Tony

 

[MDJ]

Thats if you can find a spark who will certify someone else's work tony, anyhow as for the original info 4mm2 sounds alright allowing for diversity, the cooker will have a diversity allowance, I will let the debate begin regarding the existing distribution board and 3036 fuses haha.

 

[TonyH1208]

Thanks for the input Mike, it would be good if I could use the existing circuit as running a new 6mm cable is going to be a bit of a pain in the backside!!:stooge_moe:

 

[Octopus]

Hi Everyone,

My name is Tony and I've just registered.

Although I will be doing the work myself, I intend to get a professional electrician in to certify the installation afterwards.

Many thanks,

Tony

The only way this can work is if you contact LABC, pay their fees and the come and inspect it. No Part P sparkie can sign off other peoples work.

For what its worth, you should get a couple of sparkies round and get them to quote for the CU change, bonding, tails and any other sockets etc for your kitchen.

If you're going to spend thousands on a kitchen why skimp on the electrics???

And while you are pondering try looking at this:

http://www.planningportal.gov.uk/buildingregulations/approveddocuments/partp/

 

[yellowvanman]

I'm looking at running a 6mm cable from my existing consumer unit to an additional 2 to 5 way consumer unit directly above the kitchen in the eaves.

Would that be easily accessible if something tripped?

 

[telectrix]

personally, i would leave well alone. in the unlikely event of both appliances pulling full rated load at the same time ( was going to say simultaneously, but wasn't sure i could spell it ), that's only 30A @ 240V, so 4mm on a 30A is OK. you could add a stand alone MCB or even RCBO alongside the CU to give faster tripping in case of a fault.

 

[TonyH1208]

Hi Yellowvanman,

Yes, the new CU would be under the eaves and there is a door immediately beside it for easy access. We live in a dormer bungalow.

Murdoch,

Reasonable point, I may well do that. I just wanted to do as much as I could myself to save costs since, as you say, kitchen replacement is expensive. What i don't want to do do is compromise safety which is why I asked the question in the first place.

Thanks all.

Tony

 

[TonyH1208]

Thanks telectrix,

I was thinking of that if the 4mm was thought to be safe enough.

btw you spell Cimultainousleyyyy very well!! lol :stooge_moe:

Cheers,

Tony

 

[Engineer54]

Why would you want another CU in the Kitchen, when your living in a Bungalow for gods sake??. If you want extra circuit(s), either add a second CU next to the existing CU. Or better still, replace the old existing CU for a new CU with more available ways....