Please help!! electric cooker cables/ kw

[Amy1806]

Hi there. I have recently had my 2 bedroom house re-wired. I am currently looking for a cooker, preferably electric freestanding. My electrician has just informed me that I must find a cooker with a max of 9.5 kw, or buy a gas hob/electric oven combo. The reason for this is because he has installed two 6mm earth cables to connect to the cooker. What I want to know is if this is normal and can electric freestanding cookers use two cables? As it is hard to find an electric cooker under 9.5kw! and I do not want to buy a gas hob/electric oven combo as my kitchen is not fitted for this.
Thank you.

 

[flameport]

The normal arrangement for a cooker would be a 32A circuit wired in 6mm cable.
That will be suitable for the vast majority of situations.

The total rating of the cooker is largely irrelevant.
Suggest you buy whatever cooker you want, and get a new electrician to install it.

If they really have installed two 6mm cables, those would probably be capable of supplying your entire house, never mind a single appliance.

 

[EFLImpudence]

My electrician has just informed me that I must find a cooker with a max of 9.5 kw,

Rubbish

or buy a gas hob/electric oven combo.

That may be a good idea, regardless.

The reason for this is because he has installed two 6mm earth cables to connect to the cooker.

If you mean two 6mm² twin and earth cables then, theoretically, you could have two 19kW cookers.

What I want to know is if this is normal and can electric freestanding cookers use two cables?

You could connect two cables to one cooker but it will not be necessary.

As it is hard to find an electric cooker under 9.5kw! and I do not want to buy a gas hob/electric oven combo as my kitchen is not fitted for this.

Ok.

Nearly every cooker in the country will be connected to one cable of 6mm² on a 30A fuse or 32A circuit breaker.

With this arrangement you can safely have a cooker up to 15kW.
This is because of what we call 'diversity' where, because all the elements in the cooker will be controlled by thermostats and so not on for very long or all at the same time, seemingly large loads can be connected to seemingly small circuits.

Your electrician sounds very inexperienced or was it an 'electrician' from a shop?

 

[PrenticeBoyofDerry]

My electrician has just informed me that I must find a cooker with a max of 9.5 kw,

That would no restrict you form buying a lesser rated cooker!

or buy a gas hob/electric oven combo. The reason for this is because he has installed two 6mm earth cables to connect to the cooker.

can't see the logic in that statement, with regards to output power.

What I want to know is if this is normal

It not normal on a rewire, unless, the electrician, was installing two separate circuit, one for electric hob and one for oven.

and can electric freestanding cookers use two cables?

Yes

 

[kevnurse]

You wrote that it was your house. Are you the owner? If so, under what authority did the "lecky" install wiring without speaking to you first about how you intend to cook in the kitchen?

Anyway, the guy is clearly not a lecky, for the reasons others have quoted above.

The answer lies in electrical load diversity (google it). Go and buy whatever freestanding cooker you want and kick the lecky's ar$e while you're at it and employ someone else who knows what they are doing, to connect it

 

[Amy1806]

Thank you everyone.
Basically I think he assumed that I wanted a gas hob /electric oven so installed two 6mm cables instead of one. However this is not what I want and now it seems that freestanding electric cookers are mostly above 9.5kw. He said that if i can find an electric freestanding cooker with 2 separate connections (one for hob, one for oven) that would work otherwise I can't buy an electric oven over 9.5kw, but looking around this is hard to find.
He has been pretty incompetent throughout unfortunately.[/code]

 

[Iggifer]

EFLI has said you can have a cooker up to 15kW, looks like you missed this and the reasoning so here you go.

Cookers are rarely ever used to their full capacity so 15kW is really more likely 6kW.

The way you calculate it is:

the first 10a + 30% of the remainder + 5a for a socket outlet in cooker control unit (CCU)

So, working back from a 15kW cooker

15000 / 230 = 65.22a

10 + 0.3x55.22 + 5 = 31.57a

Assuming you have a socket outlet on your CCU and the 6mm cable is connected to a 32a breaker

Try looking for 15kW cookers, much more scope

 

[PrenticeBoyofDerry]

Basically I think he assumed that I wanted a gas hob /electric oven so installed two 6mm cables instead of one.

Stiil doen't make sense, unless provisions were being made for the alternative of two supplys, one for electric oven and one for electric hob?
The ignition on a gas haob would not warrant installing 6.00mm T&E.

He said that if i can find an electric freestanding cooker with 2 separate connections (one for hob, one for oven) that would work otherwise I can't buy an electric oven over 9.5kw,

Excuse my French "bolas!"

He has been pretty incompetent throughout unfortunately.

Which your evidence proves!

A 15kW cooker can be installed on a 32A supply, which 6.00mm T&E will deal with providing no derating factors, with regards to method of installation.

 

[Amy1806]

Thank you again, it's all a bit confusing to me. This is one of his emails he sent to me explaining why-

The cables installed are sufficient to power a seperate cooker and hob each upto 9.5kw which for the size of the house and kitchen is ample, and again will power a lot of cooker/hob units, i can say with confidence that a 9.5kw oven/hob combo is sufficient power for most needs. the reason for not installing any other sized cable is because as general use and rule the 6mm cable is usually ample size to carry the current for the hob or oven. An upgrade in cable is usually as i said not needed and as there were specific plans for the kitchen i installed the two 6mm cables instead of just the one. im sorry if this was not explained fully at the time of installation of the cables. i was assuming that there would be two separate appliance outlets. one for the hob and the other for the oven. the best combination ovens that you can get are a mix of gas hob and electric oven, i cant remember was there a specific reason as to go for the fully electric combo, i know we spoke about it at somepoint but cant remember

He has said before the best option for me is gas hob, electric oven but surely the gas is completely separate & cannot be fitted to the 6mm cable? Plus i never once mentioned this is what I wanted.

 

[EFLImpudence]

Do you have two cooker switches on the wall?
Or is the kitchen still not finished?

Where do these two cables exit the wall?

 

[xr4x4]

What about a double oven and a electric hob, they a would pretty much need a 6mm2 each..

 

[PrenticeBoyofDerry]

Thank you again, it's all a bit confusing to me.

What the electrician was stated in the email, sound fair enough to me, not strictly correct in the calculation of maximum demand for the appliances though.
I think you may have misinterpreted this information.

You have two separate circuits for cooking appliances, both in 6.00mm T&E.
The options are to have an electric oven on one circuit.
with either a gas hob or an electric hob on the second circuit.
With a suggestion that having a gas hob and an electric oven would be wise.
which I agree with.
He has stated values of output, but actually without diversity and the difficulty of purchasing 45A MCBs the likely output on full load would be 9.2kW. But as diversity can be offered to the appliances that value would increase.

 

[Amy1806]

What about a double oven and a electric hob, they a would pretty much need a 6mm2 each..

Yes he said a freestanding electric cooker would be ok if it has two separate units, one for hob and one for oven, but do freestanding electric cookers have two separate connections?
thanks for your help.

 

[PrenticeBoyofDerry]

Yes he said a freestanding electric cooker would be ok if it has two separate units, one for hob and one for oven, but do freestanding electric cookers have two separate connections?
thanks for your help.

They do not require two connections, the two circuits installed by your electrician are for two independent appliance not a combined one!
Use both if you have two different appliance, if you have an appliance with both oven and hob just connect to the one circuit. Keep the spare isolated.

 

[Amy1806]

Thank you again, it's all a bit confusing to me.

What the electrician was stated in the email, sound fair enough to me, not strictly correct in the calculation of maximum demand for the appliances though.
I think you may have misinterpreted this information.

You have two separate circuits for cooking appliances, both in 6.00mm T&E.
The options are to have an electric oven on one circuit.
with either a gas hob or an electric hob on the second circuit.
With a suggestion that having a gas hob and an electric oven would be wise.
which I agree with.
He has stated values of output, but actually without diversity and the difficulty of purchasing 45A MCBs the likely output on full load would be 9.2kW. But as diversity can be offered to the appliances that value would increase.

Thank you for this. I know that he suggests the best option is gas/electric combo and maybe it is but if i want a freestanding electric cooker (as this is what my kitchen is fitted for) is this still do-able with these cables and restrictions? He did not inform me about any of this when re-wiring & I have always intended on buying a freestanding electric.
Thanks again for your time.