Replacement Hob Question of Available KW Load

S

src1

Joined
22 Jan 2011
Messages
8
Reaction score
0
Location
Herefordshire
Country
United Kingdom
The double oven and separate electric hob share a 40 amp supply. I believe this to be on a 6mm cable rounding the distance up to 15 metres through the walls. Both have their own individual fuses with an available socket, this is not used. The double oven is 5.4kw. The separate electric hob is 5.9kw. The hob needs to be replaced and we are considering an induction hob but first we need to understand what our limitations are for the replacement hob. Upgrading the wiring could be a real pain and may not be an option. So I would appreciate a little advice on the total kw load that I can consider for the replacement hob.

While I’m currently looking at electric and induction hobs I see that some share the same kw loadings so in this case I guess that any decision is between an individual’s preferences rather than electrical loading.
 
Any domestic hob can be used. 4mm cable on a 32 amp circuit is quite OK. Who ever did your setup wasted money and the planets valuable resources of copper. Google diversity.
 
Really appreciate the swift response, this is my first post regarding this job so the advice and guidance is a great help, thankyou!

Apologies my comment "both have their own individual fuses" was incorrect, I should have said the double oven and electric hob both have their own red off switch with a plug socket that is wall mounted near the appliance.

Both share the same 40 amp from the fuse board.

I have just been looking at Siemens EH645FEB1E induction hob, although this has a total KW7.4 rating its also has a 20 amp rating and fits straight into the worktop. https://www.johnlewis.com/siemens-eh645feb1e-induction-hob-black/p3255902
 
Because of the concept of 'diversity', which takles into account the fact that all parts of cooking appliances will not simultaneously be drawing their maximum current for appreciable periods of time, a 32A circuit can support up to a total of about 19kW of cooking appliance loads, and a 40A one nearly 24kW total.

Kind Regards, John
 
Thanks Winston1, Ban-all-sheds and John much appreciated, i will take some time as I look into this a little more and will probably return to pop a few more questions.
 
src1 said:
the double oven and electric hob both have their own red off switch with a plug socket that is wall mounted near the appliance.
Click to expand...
OK.

FYI, if you are ever having a new kitchen and associated upheavals, those switches are not mandatory, so if you don't want them you can get rid of them.


Both share the same 40 amp from the fuse board.
Click to expand...
As others have said, cooking appliance circuits are not designed on the basis of the theoretical maximum load, because once an oven or hob zone is up to temperature it switches off, and then cycles on/off to maintain the required temperature. A heating element is not "dimmed" like a light is - it is either 100% on or it is off, but averaged out the load is assumed to be a lot less than the maximum.

You can read about it here: http://www.tlc-direct.co.uk/Book/6.2.1.htm

I have just been looking at Siemens EH645FEB1E induction hob, although this has a total KW7.4 rating its also has a 20 amp rating
Click to expand...
And there you have it.

7.4kw @ 230V is 32A

30% of 32A + 10A = 19.6A

Even though your oven is separate I would say you do the diversity calculation on the total, i.e. 12.8kW -> 26.7A. You're supposed to add 5A for the socket, so even accounting for your two that's 37A, i.e. within the circuit limit.


and fits straight into the worktop. https://www.johnlewis.com/siemens-eh645feb1e-induction-hob-black/p3255902
Click to expand...
The only thing I would advise about that is that you consider the practicality of touch controls, and controls built into the hob like that.

Firstly, to adjust any "ring" you have to first select it, and then start swiping your finger. That is nowhere near as fast as having dedicated knobs which can, if necessary, be twiddled two at a time.

Secondly, you might have problems accessing the controls in the first place. This is how that hob would play with my largest pan in use:

upload_2018-10-21_23-39-41.png
upload_2018-10-21_23-40-22.png


Rather impractical.

IMO, designs like that are a triumph of trivial cosmetic appearance over sound functionality.
 
ban-all-sheds said:
7.4kw @ 230V is 32A

30% of 32A + 10A = 19.6A

Even though your oven is separate I would say you do the diversity calculation on the total, i.e. 12.8kW -> 26.7A. You're supposed to add 5A for the socket, so even accounting for your two that's 37A, i.e. within the circuit limit.
Click to expand...
You forgot to deduct 10A first. Doesn't make a huge difference.

16.7 & 23.7
 
Last edited:
src1 said:
the double oven and electric hob both have their own red off switch with a plug socket that is wall mounted near the appliance.
Click to expand...
I am sorry, me no understand this. What do you mean by a "plug socket".
I'm not being pedantic about terms. What DIYers call a plug socket is really a socket like this
AA113SS.JPG

into this goes a plug
TLPT13.JPG

and this has a fuse in it, maximum size 13amp.

13amp is not big enough for the double oven or for the proposed hob.
Can you describe what you mean. Or take a photo of what you have that connects the appliances to the power.
 
.....or do you mean that each appliance has one of these
AA45CCU.JPG

with the appliances being directly connected to some sort of connection plate?
 
Taylortwocities said:
I am sorry, me no understand this.
Click to expand...
Really?



What do you mean by a "plug socket".
I'm not being pedantic about terms. What DIYers call a plug socket is really a socket like this
Click to expand...
Yes, a socket for a plug.

Not a socket for the head of a bolt.

Or a socket for the end of a ball on a bone.


Can you describe what you mean. Or take a photo of what you have that connects the appliances to the power.
Click to expand...
I really am so looking forward to the fun that will ensue when you try to claim that you really had no idea that he meant something like this:

CM2456.JPG


Please don't wait too long, as I need to get to bed.
 
You must log in or register to reply here.
Back
Top