Electric Cooker

[AMS1]

My other half is looking to buy an electric cooker for his house he's hoping to rent out.

Most of the cookers he likes are around 9KW+ and in the specs they all say that the fuse rating is 32amps (which is what he's got).

However, his electrician says that he should get an oven no greater than 7.8KW as anything 9+ needs a 40amp fuse.

So who's right? If it's the electrician then isn't it a bit irresponsible for the specs to say only 32amps are needed?

 

[EFLImpudence]

Ninety percent (if not more) of homes in Britain have a 32A Cooker circuit - usually with 6mm² cable (which is excessive since the introduction of MCBs).

This circuit is good for cooking appliances up to 15kW (or 19kW if there is not a socket integral with the cooker switch)

Get a different electrician.

 

[Taylortwocities]

Get a different electrician.

 

[AMS1]

Thank you for the replies.

This is awkward then, as my OH's electrician is a football mate of his . My OH would really prefer a higher wattage oven, but when it came to fitting it his mate will probably take the hump with us for doubting/disregarding his advice.

I did think it a bit strange that the suggested fuse amp that the website was stating was lower than what his mate recommended, but then what about W=A x V ?

(not that I care much, it won't be my oven and it won't be in my house, but my curiosity is piqued now)

 

[Taylortwocities]

We apply a technique called "diversity" to allow electrically a quart to fit into a pint pot. There's detail here. https://www.tlc-direct.co.uk/Book/6.5.2.htm
Suggest the "electrician" looks at his On Site Guide!!

 

[JohnW2]

I did think it a bit strange that the suggested fuse amp that the website was stating was lower than what his mate recommended, but then what about W=A x V ?

Having worked out the maximum current, using "W=A x V", one then applies the concept of 'diversity' (which your electrician clearly has not heard of), which takes into account the fact that not all bits of a cooking appliance will be drawing current at the same time.

As an example, your 9 kW oven/cooker, if that power is stated for 230V (which it probably isn't!) represents about 39A (9000/230). Diversity says that one considers the current to be the first 10A of that, plus 30% of the rest - hence 10A + (30% of 29A), which comes to about 18.7A - very much within the capabilities of your 32A circuit.

Kind Regards, John

 

[AMS1]

Thank you so much for your replies - I really appreciate it.

This just reminds me why I spent most of my time as a teenager staring out the window during physics lessons. Clearly I should have paid more attention.

 

[ban-all-sheds]

Tmy OH's electrician is a football mate of his

Mate he may well be.

Electrician he most definitely is not. He may think he is. He may even have a bit of paper showing that he has some electrically-related mickey-mouse qualification, but he is deluded if he thinks that makes him an electrician.

This is such basic, basic stuff, it makes me wonder, and should make you really worry, that if he doesn't know or understand it what else is he going to get wrong?

 

[ban-all-sheds]

As an example, your 9 kW oven/cooker, if that power is stated for 230V (which it probably isn't!) represents about 39A (9000/230). Diversity says that one considers the current to be the first 10A of that, plus 30% of the rest - hence 10A + (30% of 29A), which comes to about 18.7A - very much within the capabilities of your 32A circuit.

FYI - doing the calculation in the other direction shows that a 32A circuit is OK for a cooker of up to 19kW.

Although in reality a cooker that big might well betoken usage not typically domestic, so one might be a little more conservative.

But up to 12-odd kW? No problem at all.

 

[JohnW2]

FYI - doing the calculation in the other direction shows that a 32A circuit is OK for a cooker of up to 19kW.

It does, and EFLI made that very point in the first reply (post #2) in this thread.

Kind Regards, John

 

[ban-all-sheds]

Speed reading is a bit like speed driving - sometimes it goes wrong.

 

[stillp]

Speed reading is a bit like speed driving - sometimes it goes wrong.

The consequences are a little better though.

 

[ban-all-sheds]

Unless you are very unfucky

 

[stillp]

Unless you are very unfucky

Freudian?

 

[Taylortwocities]

It depends on how quickly you read it