What amp circuit required for 2 ovens and a hob

[mav567567]

I am looking to replace a freestanding stove with 2 x 16amp single ovens and an inductions hob at 32amp.

Ovens are 3.8kw and hob is 7.35kw.

Currently there is a feed going to the stove thats on a 32amp fuse. Is this sufficient.

Putting in another cable doesnt seem to be an option due to underfloor heating and it doesnt appear possible to pull through a cable to the island where the kit will be located.

Electrician has said it needs more but ive read on forums that 32 should be enough.

I Would be so grateful for a clear answer on this as i thought this would be black or white yet it appears to divide people.

 

[Murdochcat]

Your “electrician” needs to read up on diversity

 

[mav567567]

This is what ive come across. But why would an electrician not know about diversity.

 

[JohnD]

This is what ive come across. But why would an electrician not know about diversity.

Maybe if he was unqualified? Or incompetent?

 

[SUNRAY]

I am looking to replace a freestanding stove with 2 x 16amp single ovens and an inductions hob at 32amp.

Ovens are 3.8kw and hob is 7.35kw.

Currently there is a feed going to the stove thats on a 32amp fuse. Is this sufficient.

Putting in another cable doesnt seem to be an option due to underfloor heating and it doesnt appear possible to pull through a cable to the island where the kit will be located.

Electrician has said it needs more but ive read on forums that 32 should be enough.

I Would be so grateful for a clear answer on this as i thought this would be black or white yet it appears to divide people.

Bear in mind the MI's will likely require 16A fuse or MCB each for the ovens.

 

[JohnD]

Bear in mind the MI's will likely require 16A fuse or MCB each for the ovens.

Unless the MIs are written for the UK market, of course.

 

[SUNRAY]

Unless the MIs are written for the UK market, of course.

?

 

[JohnD]

Some countries have 16A sockets, and some ovens are designed to be used in such countries, and their MIs sometimes say " your oven must be plugged into a socket fused at 16A," or similar wording.

Ovens which are designed for use in the UK should not include such wording.

UK single ovens are usually designed to work with a 13A plug.

Double ovens, not.

We are assuming that the OP is in UK but we don't know what ovens he intends to buy.

 

[SUNRAY]

Some countries have 16A sockets, and some ovens are designed to be used in such countries, and their MIs sometimes say " your oven must be plugged into a socket fused at 16A," or similar wording.

Ovens which are designed for use in the UK should not include such wording.

UK single ovens are usually designed to work with a 13A plug.

Double ovens, not.

We are assuming that the OP is in UK but we don't know what ovens he intends to buy.

Ovens are 3.8kw

Not likely to come with a 13A plug.

 

[mav567567]

Ovens are 16amp 3.8kw and need to be hardwired. Applying diversity i was coming up with a figure just shy of 29 amps as there is no additional socket. Ive read that diversity should not be applied to induction hobs but again there is alot of opinion out there on this.

Bottom line, should we be ok with this or could we run into issues.

 

[EFLImpudence]

Aren't induction hobs supposed to be more efficient and use less electricity so why would diversity not apply to them?

 

[Adam_151]

Aren't induction hobs supposed to be more efficient and use less electricity so why would diversity not apply to them?

A little bit more efficient, yes, with the added compliaction of the fact that the 'burners' are not of a fixed power, they have the ability to be driven at a wide range of power settings depending on the cooking task, so you could be running one ring at quite a bit the 2kw you'd get on a normal hob, obviously the control logic of the hob will not let you exceed a total maximum, which is usually 7kw by default although many can be set lower (although doing so somewhat cripples the usfulness of it), an induction hob under heavy use is going to spend more time closer to its max draw than a convential hob, but probably not a lot more. I wouldn't suggest that diversity shouldn't be applied to induction hobs, but maybe err slightly more on the side of caution than the standard guidelines, given that they were drawn up from empiral data on conventional cooking appliances from studies done 50 years ago.

My gut feeling would be to assess installation method of existing cable, if 6mm there is posisbly a good chance it could go on a 40A breaker, and thebn put a couple of 16A and one 32A breaker in an enclosure in one of the units near the ovens and if you are luckly with positioiung then the flexes to the appliances can come straight into it through stuffing glands with no messing around (Assume there is an isolator on the incomming supply - check thats suitably rated). If the supply had to remain at 32A then 95% you'd get away with it, but if you don't, it'll probably be at christmas or other inconvieninet time. Check the RCD as well, if its type AC then it really needs upgrading to A if introducing an induction hob.

 

[EFLImpudence]

A little bit more efficient, yes, with the added compliaction of the fact that the 'burners' are not of a fixed power, they have the ability to be driven at a wide range of power settings depending on the cooking task, so you could be running one ring at quite a bit the 2kw you'd get on a normal hob, obviously the control logic of the hob will not let you exceed a total maximum, which is usually 7kw by default although many can be set lower (although doing so somewhat cripples the usfulness of it), an induction hob under heavy use is going to spend more time closer to its max draw than a convential hob, but probably not a lot more. I wouldn't suggest that diversity shouldn't be applied to induction hobs, but maybe err slightly more on the side of caution than the standard guidelines, given that they were drawn up from empiral data on conventional cooking appliances from studies done 50 years ago.

But surely taking all that into consideration - and anything else you care to mention - as you say, they cannot possibly draw more than the elements' maximum rating; which is no more than conventional; so must be drawing the same or less than a conventional hob at any particular time.

Therefore if they are more efficient in that less heating is wasted, then how can the same - or better - diversity not be applicable.

My gut feeling would be to assess installation method of existing cable, if 6mm there is posisbly a good chance it could go on a 40A breaker, and thebn put a couple of 16A and one 32A breaker in an enclosure in one of the units near the ovens and if you are luckly with positioiung then the flexes to the appliances can come straight into it through stuffing glands with no messing around (Assume there is an isolator on the incomming supply - check thats suitably rated). If the supply had to remain at 32A then 95% you'd get away with it, but if you don't, it'll probably be at christmas or other inconvieninet time. Check the RCD as well, if its type AC then it really needs upgrading to A if introducing an induction hob.

Ah. The old gut feeling and Christmas reasoning.

Is there anything official to confirm your gut? If not, then ...

 

[EFLImpudence]

The OP has stated that there is no socket on the cooker switch therefore with 14.95kW of appliances there is still 5kW "to play with" for the usual diversity arrangement. Is this not enough to accommodate an induction hob even if it were different than a conventional hob?

Incidentally 14.95kW after diversity is 25.7A - not 29A as stated above.

 

[SUNRAY]

Ah. The old gut feeling and Christmas reasoning.

Is there anything official to confirm your gut? If not, then ...

Not a silly one as it goes.