Yet Another Cycling Forum

General Category => The Knowledge => OT Knowledge => Topic started by: velosam on 14 April, 2019, 09:13:40 pm

Title: Induction hobs and electric ovens and new electric cabling
Post by: velosam on 14 April, 2019, 09:13:40 pm
I would like to replace my gas cooker and oven with an induction job and electric fan assisted oven.

I have a 13amp supply in kitchen but not a switched supply.

I realise I can now buy a 13amp induction hob and oven, which means I don’t have to run a new cable from my fuse box.  It isn’t a problem as I have limited furniture and the carpet can easily be raised.

The advantage of not running a new cable is cost but I would be sill not to do it now if that is more advantageous.

Should I go with the 13amp stuff which saves the cost of cabling (albeit not a lot as some cabling still has to be done for the 13amp supply)?

Thanks
Title: Re: Induction hobs and electric ovens and new electric cabling
Post by: Diver300 on 14 April, 2019, 09:21:33 pm
I assume that you would be looking at a hob rated at 13 A and an oven, also rated at 13 A, that plugs into a separate socket.

An oven that takes a 13 A feed is no problem. Ovens rarely take much more and limiting to 13 A just slows the warm-up down a bit. Obviously you have to buy and oven that is rated to 13 A or comes with a normal plug.

I'm in two minds about a 13 A  feed to an induction hob. In theory, it could be very limiting, as they are are often 2 kW for each larger ring, and maybe 1.5 kW for a small ring, so limiting to 13 A or 3 kW total seems like it would be a problem. However, my sister-in-law has an induction hob with just a 13 A plug and it's fine.
Title: Re: Induction hobs and electric ovens and new electric cabling
Post by: grams on 14 April, 2019, 10:50:12 pm
If you're get the 13A stuff and run it on an existing circuit you might be pushing the limits - I'd expect kitchen sockets to be on a 20A breaker which doesn't leave you much room* if you want to run the hob and/or the oven and/or kettle/toaster/etc at the same time. It shouldn't be *dangerous* if your wiring was done properly, but it may lead to the breaker tripping regularly. If you have a 32A ring main or an existing "cooker" socket on a separate circuit you shouldn't need to worry so much.

(* note that "20A" breakers can take currents significantly above 20A for several minutes before they trip, so you'd be ok e.g. boiling the kettle while using the hob. This isn't dangerous as it's designed to reflect how long the wiring can carry high currents before it might start to overheat, and there are also *huge* safety margins built into British wiring standards)
Title: Re: Induction hobs and electric ovens and new electric cabling
Post by: Wowbagger on 15 April, 2019, 02:09:13 pm
For about 3 years we have quite happily run one of these from the same double 13A socket as our kettle with no problem at all:

https://www.argos.co.uk/product/9147782
Title: Re: Induction hobs and electric ovens and new electric cabling
Post by: Diver300 on 15 April, 2019, 02:42:43 pm
For about 3 years we have quite happily run one of these from the same double 13A socket as our kettle with no problem at all:

https://www.argos.co.uk/product/9147782
Yes, but a single hob (2 kW) is a very different animal from a built-in 4 ring hob, with 2 x 2 kW + 2 x 1.5 kW, which adds up to 7 kW. 13 A is approx 3 kW at 240 V.

We used a cheap Aldi/Lidl version of that plug-in single ring induction hob for a few months and it was one of the things that sold us on having a built-in induction hob.
Title: Re: Induction hobs and electric ovens and new electric cabling
Post by: hbunnet on 15 April, 2019, 02:57:53 pm
We have a 4 ring induction hob on a 13A circuit.  There was a setting in the set up to allow this.
I think there are some clever electronics to allow it.

There is no apparent loss in performance and it is much faster to heat up when compared with other hobs we have used in e.g. holiday houses.
Title: Re: Induction hobs and electric ovens and new electric cabling
Post by: Edd on 15 April, 2019, 03:02:34 pm
Check with an electrician to see how much it costs to stick in a 32A circuit, if you are happy with them using trunking rather than chasing the walls/pulling up floorboards it may not be too expensive even
Title: Re: Induction hobs and electric ovens and new electric cabling
Post by: Diver300 on 15 April, 2019, 03:48:12 pm
We have a 4 ring induction hob on a 13A circuit.  There was a setting in the set up to allow this.
I think there are some clever electronics to allow it.

There is no apparent loss in performance and it is much faster to heat up when compared with other hobs we have used in e.g. holiday houses.
Have a setting in the software for that would make me a lot happier with 4 rings on 13 A. It shows that the manufacturer has realised that you can't take 30 A from a 13 A circuit, and that cutting down all the rings when someone tries may be noticeable in some circumstances.

My sister-in-law has not noticed any loss in performance, and I can see that it must be very, very rare for a normal household to use more than 3 kW on an induction hob for any length of time.
Title: Re: Induction hobs and electric ovens and new electric cabling
Post by: pcolbeck on 15 April, 2019, 03:50:43 pm
Check with an electrician to see how much it costs to stick in a 32A circuit, if you are happy with them using trunking rather than chasing the walls/pulling up floorboards it may not be too expensive even

If you have to run a new circuit anyway go 32 amp The cost difference between 13 amp and 32 amp cable compared to the cost of the labour to run it (which will be the same for both)  will not be very much at all then you can stop worrying and buy whatever cooker takes your fancy.
Title: Re: Induction hobs and electric ovens and new electric cabling
Post by: grams on 15 April, 2019, 03:58:11 pm
Have a setting in the software for that would make me a lot happier with 4 rings on 13 A. It shows that the manufacturer has realised that you can't take 30 A from a 13 A circuit, and that cutting down all the rings when someone tries may be noticeable in some circumstances.

Not all of them are settable - I think it's more common for there to be different models, and the 13A ones come with a normal mains plug.

The only 13A one I've seen up close blocks you from turning up the power on any ring when you hit the 13A limit until you turn another ring down. I don't know if there are cleverer systems that manage to do this invisibly.

Anyway, the point isn't that a four ring one might take more than 13A, it's that if you're using more than one ring you might spend more time close to 13A, meaning using another appliance or more likely to trip the breaker on a typical 20A circuit.
Title: Re: Induction hobs and electric ovens and new electric cabling
Post by: velosam on 15 April, 2019, 05:29:17 pm
Thanks all.

I got a few quotes.  The extra trunking, lifting up floorboards etc is £150 more and then it’s done for good.

I can skimp in other things like a cheap oven combo so I may just get it done.

Title: Re: Induction hobs and electric ovens and new electric cabling
Post by: simonp on 15 April, 2019, 09:54:10 pm
I think that’s the right choice. I’m currently using one ring on ours to bring a pan to the boil. 3.6kW.