Install new oven & induction hob to existing circuit

[Steve D]

Hi All. Just a little help I need connecting a electric oven and induction hob. The existing is a 32 amp MCB in the consumer unit. A 4m run of 6mm sq t&e cable from mcb going to a 45A cooker control switch. From here a 6mm sq t&e going into cooker connection unit. I have removed the old electric oven which was connected to the cooker connection unit with 6mm sq t&e cable. I want to connect a new 2.5kw oven and a 6.4kw induction hob. I have a 45 Amp Dual Appliance / Cooker Outlet Plate which will replace the existing cooker connection unit. Is it ok to connect both appliances to the new dual appliance connection unit so they are on the same circuit. If so then what size cable do I need to connect the oven to the connection unit. The hob already has a 5 core cable with the blue and grey cable joined together at the end and the black and brown also joined together. It looks like a 3 phase cable. Any help on this will be much appreciated.
Thanx

 

[buzzlightyear]

read the manufactures instructions in doubt consulate a qualified spark ,it must be us then ,not pay someone to sort it out then .

 

[ipf]

Stanley Unwin strikes again, eh, buzz...….

As regards the question, buzz ain't far off.

 

[Steve D]

My Sparky is not available at the moment. I'm here in the kitchen fitting units and have come to the oven part of the installation. I need to get this kitchen finished quite quickly. In the instructions there's nothing about connecting 2 appliances to the same circuit.
Thanx

 

[buzzlightyear]

My Sparky is not available at the moment. I'm here in the kitchen fitting units

i have just put the pop corn in .back in 5 minutes.

 

[Steve D]

"Star command calling buzzlightyear." Need your help to save me from my wife.
"STEVEN When are you going to finish that kitchen"
Oh no she's coming with the rolling pin to whip my ---

 

[FatAlan]

If you look at the OSG in respect of ovens and hobs etc and applying diversity taking into account your cable size and length, you’ll get your answer.

 

[buzzlightyear]

Pop corns ready.LoL.
the op has not got OSG he wants to put it in him self .saving a few bob.
who blame them for doing us out of a job .cause it cost us loads of moines.

 

[Steve D]

Not trying to save a few bob. Just trying to save time. If Its possible to connect both to the existing then I'll do it now. So that I can continue with installing the oven housing cabinet then at least I'll have the wiring ready.

 

[telectrix]

yes you can connect both into a dual connection unit. the 32A MCB and 6.0mm will be fine. just follow manufacturers instructions for final connection/s.

 

[TheReturnOfHightower]

The fact that a simple question like this took until the 9th response to get something sensible is a bit sad.

 

[Steve D]

Thanks for your help Telectrix and your time. Much appreciated.

I have read the manufacturers instructions.
and it says "This appliance must be connected directly to the mains using an omnipolar circuit breaker with a minimum opening of 3mm between contacts"
Then it goes on to say in adifferent paragraph "This appliance requires a 32amp miniature circuit breaker"

 

[Bobster]

Domestic - Wiring up an induction hob - wanted to sense check if what I'm doing is correct - https://www.electriciansforums.co.uk/threads/wiring-up-an-induction-hob-wanted-to-sense-check-if-what-im-doing-is-correct.172663/page-2#post-1517689

 

[telectrix]

deflated'

 

[John Preston]

The induction hob draws quite a bit of current. On its own I would say it's spot on using a 32amp mcb and 6mm twin & earth however, adding another 2.5kw (oven) to the equation this would/could tip it over the edge at around 38A in total. (not knowing the reference method it's difficult to say) There is every chance that each appliance could be used to its full capacity when doing a lovely Sunday roast for example. Most modern ovens are designed to simply plug into the ring circuit so does the oven have a 13amp plug on it? This is why it's never a simple answer unless we know all the facts. Some answers/comments sound a little "unhelpful" but we don't know the full picture.

 

[Steve D]

Thanks for your help John.
I actually have 2 kitchens in my property. I wouldnt run the new oven and hob at the same time as I have a 5 burner gas hob in the other kitchen.

 

[Andy78]

Thanks for your help John.
I actually have 2 kitchens in my property. I wouldnt run the new oven and hob at the same time as I have a 5 burner gas hob in the other kitchen.

You'd use the hob in one kitchen and the oven in another kitchen when preparing parts of the same meal ?

 

[Steve D]

Sorry missed the bit about the 13A plug. ill just check it.

 

[Steve D]

You'd use the hob in one kitchen and the oven in another kitchen when preparing parts of the same meal ?

No the oven hasnt got a 13 amp plug on it. Just the connecting block.

 

[Andy78]

No the oven hasnt got a 13 amp plug on it. Just the connecting block.

?

 

[Steve D]

You'd use the hob in one kitchen and the oven in another kitchen when preparing parts of the same meal ?

No we always cook in the other kitchen which has an oven. and a 5 burner hob
The Newly installed hob will only be used when my son cooks his fry ups. The oven in here won't run at the same time. We sometimes need to use two ovens at the same time but never two hobs at the same time.

 

[Steve D]

?

 

[John Preston]

I understand it's your kitchen Steve however it still needs to be right electrically and to the regulations. Let's say you sell the house in the future and the new owners are not aware of the "special" arrangement of the cooker and hob. I know it all sounds a bit over the top but it is a requirement to do it right. With the cooker having no plug on it this tells me it will more than likely draw a higher current than a fan assisted plug in oven which to be honest enhances the requirement of it needing another supply. The problem also is that the cooker will be backed up by a 32amp circuit breaker when in actual fact this would be too large. It should be on it's own radial backed up with a 16amp circuit breaker. If you ran a piece of 2.5mm twin and earth through the cabinets and leave it on the coil the sparky could continue to run it to the consumer unit to finish it off. This way you could finish the kitchen but not compromise the electrical installation. The induction hob can be connected to your existing 6mm supply.

 

[Steve D]

So you telling me that I do need another circuit going back to the consumer unit If so then I dont think i have any more room in the consumer unit for another fuse. Just asking the question so im prepared for the extra cost of a new consumer unit and rewiring for it when my sparky comes

 

[John Preston]

He might be able to come off the ring (socket circuit) and use a 20A double pole switch. It's just too much combined on the one circuit with your induction hob. It caught me out when I bought an induction hob to be honest. I ended up using it in my flat and using a combined induction/gas hob in the house. It was half the power as it only had two induction rings. Shout at your sparky and tell him he's needed on the job

 

[GeorgeCooke]

You can run them on one circuit. Ovens and hobs never take full load continuously. They cycle on and off. Read up on diversity. The cooker is OK on the 32 amp MCB which is there to protect the cable (which you have oversized anyway as 4mm would do) not the cooker on the end of it.

 

[Steve D]

You can run them on one circuit. Ovens and hobs never take full load continuously. They cycle on and off. Read up on diversity. The cooker is OK on the 32 amp MCB which is there to protect the cable (which you have oversized anyway as 4mm would do) not the cooker on the end of it.

Thanks for your help George.
So I can do it even though the instructions say "This appliance must be connected directly to the mains using an omnipolar circuit breaker with a minimum opening of 3mm between contacts"
Sorry about so many questions. Just want to do it right just in case my sparky doesnt get back to me soon.

 

[telectrix]

ovens and hobs up to a total rating of 15kW have been fine for the last 60 + years with both on a 32A MCB (6.0mm cable, ref. method withstanding). same loads, same electrickery these days in spite of the EU(rinal) woth their stupid cable colours and phantom 230V. why should it change?

 

[John Preston]

You can run them on one circuit. Ovens and hobs never take full load continuously. They cycle on and off. Read up on diversity. The cooker is OK on the 32 amp MCB which is there to protect the cable (which you have oversized anyway as 4mm would do) not the cooker on the end of it.

Diversity:- Dance Group Seriously though, fair enough if it's quoted somewhere that diversity is allowed for then I'll go with that.

 

[Steve D]

Thank you all for your help, advice and your time. You have been very helpful. Much appreciated.

 

[GeorgeCooke]

same electrickery these days in spite of the EU(rinal) woth their stupid cable colours and phantom 230V.

Neither of those were anything to do with the EU, but I take your point.

 

[GeorgeCooke]

same electrickery these days in spite of the EU(rinal) woth their stupid cable colours and phantom 230V.

Neither of those were anything to do with the EU, but I take your point.

So I can do it even though the instructions say "This appliance must be connected directly to the mains using an omnipolar circuit breaker with a minimum opening of 3mm between contacts"

Indeed, the instructions are guidance not law.

 

[grumpyjohn01]

ovens and hobs up to a total rating of 15kW have been fine for the last 60 + years with both on a 32A MCB (6.0mm cable, ref. method withstanding). same loads, same electrickery these days in spite of the EU(rinal) woth their stupid cable colours and phantom 230V. why should it change?

Is this your personal rule of thumb? Based on I guess a circa 50% diversity factor for the 6mm/B32 combo?

 

[telectrix]

Is this your personal rule of thumb? Based on I guess a circa 50% diversity factor for the 6mm/B32 combo?

it's a well used formula... 10A + 30% of remainder

 

[grumpyjohn01]

it's a well used formula... 10A + 30% of remainder

Just had a look at OSG (amd3, havent got latest to hand) and you are correct for assessment of load on a final circuit to use that formula, can't get 15kW though...I get 13.8 to 14.4 depending on which voltage you prefer (!) thats for 2 appliances on same circuit.

 

[John Arnold]

Steve D read the top line of the instructions again.