Cooker Wiring and future proofing

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Just having a new kitchen designed and part of this is 2x cookers (1x asks for a 13amp supply 2.8Kw the other asks for a hard wire and pulls 3.1Kw amps) i really want to future proof it if i install a bigger rated ovens/s how would i do this please and recommendations of switching.
Any help would be great thank you
 
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Sounds like you need a new circuit which is notifiable. Let you registered electrician design it as it will be his signature on the notification.
 
Do you already have a “cooker” circuit? Is this already bring used?
Are you planning an electric hob too?
 
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To really future proof it, run two 6.0 mm2 T+E cables from the consumer unit.

More than you will ever need, probably, but very future proof.
 
2x cookers (1x asks for a 13amp supply 2.8Kw the other asks for a hard wire and pulls 3.1Kw amps) i
2x 16A circuits.
or 2x 20A circuits
or 1x 25A circuit
or 1x 32A circuit
Other options are available.

Cookers are not ovens, and 'future proofing' is impossible.

However the general trend for appliances is that they are a lower power rating and use less energy than their predecessors, so it's rather unlikely that any replacement would require a higher rated circuit than those you intend to install now.

You will need a circuit for an electric hob, as in the future, gas is going away.
 
The future proof is so hard, and the specifications for ovens and hobs don't help.

It is clear you can't supply an oven with a 100 amp supply, there is no internal fuse with most ovens, so the supply must auto disconnect with a fault, but not actually seen an upper limit on the supply with any installation instructions.

Often there is a lower limit, but the big problem is a fuse connection unit has a limit of 13 amp. Once 13 amp (3 kW) is exceeded you need a supply from a large unit, most people don't want something like this
upload_2022-3-27_11-14-22.png
in there kitchen, in fact mothers house we did have a mini consumer unit in the kitchen, but that was because the house needed rewiring and my dad refused to have it done.

If we could buy a 16 amp fused connection unit it would be easy, but not freely available in the UK. So we look at tradition, and traditionally in the UK cookers are supplied with a 30 or 32 amp supply, and traditionally we have used twin cooker connection units, so be it two ovens, or a hob and an oven, to use a 32 amp supply to a twin cooker connection unit is the traditionally method.

However I have looked at the internal wiring on an oven, and it does not really seem man enough to handle 32 amp, we are really relying on under fault conditions there will be an earth fault and the RCD will auto disconnect.

Using 16 amp supplies to ovens seems better, however I would use 4 mm² or 6 mm² so it can be up-rated in the future, however for this to happen we need the paperwork to show the circuit was designed for a 32 amp supply, even if a 16 amp MCB or RCBO has been used.

Most installation certificates do give the cable size, but it also needs to give installation method and most of the installation certificates fail to give installation method, and also of course need to be sure that is the latest certificate.

I mislaid the certificates when I came to sell mothers house, in the end I did find them, but realised there was some overlap, kitchen was done, then the wet room, then full rewire and it was impossible from the paperwork to say what certificate covered what.

I know the original hob in my mothers house was an induction hob, and the wiring was installed with a 32 amp RCBO, but the induction hob raised questions as if suitable with mother pace maker, and also the display could not be seen at the angle of ones eyes to the hob when sitting in a wheel chair, so it was changed to a halogen domino hob which only needed a 16 amp supply, so the RCBO was changed to 16 amp. There was nothing on the paperwork to say this had happened, and if the new owners wanted to swap back to a 4 ring hob, their only way to find out would be to ask me or the installer.

We can assume when we see 6 mm² cable that we can fit a 32 amp RCBO, but it that good enough? For all we know the 6 mm² could be because the cable goes through thick insulation so reference method 103# so 23.5 amp limit. With 4 mm² a 17.5 amp limit and I have seen nothing on the installation certificated to say what the worst reference method is.

So it is only future proof if the installation certificate includes the installation method.
 

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The future proof is so hard, and the specifications for ovens and hobs don't help.

It is clear you can't supply an oven with a 100 amp supply, there is no internal fuse with most ovens, so the supply must auto disconnect with a fault, but not actually seen an upper limit on the supply with any installation instructions.

Often there is a lower limit, but the big problem is a fuse connection unit has a limit of 13 amp. Once 13 amp (3 kW) is exceeded you need a supply from a large unit, most people don't want something like this View attachment 265408in there kitchen, in fact mothers house we did have a mini consumer unit in the kitchen, but that was because the house needed rewiring and my dad refused to have it done.

If we could buy a 16 amp fused connection unit it would be easy, but not freely available in the UK. So we look at tradition, and traditionally in the UK cookers are supplied with a 30 or 32 amp supply, and traditionally we have used twin cooker connection units, so be it two ovens, or a hob and an oven, to use a 32 amp supply to a twin cooker connection unit is the traditionally method.

However I have looked at the internal wiring on an oven, and it does not really seem man enough to handle 32 amp, we are really relying on under fault conditions there will be an earth fault and the RCD will auto disconnect.

Using 16 amp supplies to ovens seems better, however I would use 4 mm² or 6 mm² so it can be up-rated in the future, however for this to happen we need the paperwork to show the circuit was designed for a 32 amp supply, even if a 16 amp MCB or RCBO has been used.

Most installation certificates do give the cable size, but it also needs to give installation method and most of the installation certificates fail to give installation method, and also of course need to be sure that is the latest certificate.

I mislaid the certificates when I came to sell mothers house, in the end I did find them, but realised there was some overlap, kitchen was done, then the wet room, then full rewire and it was impossible from the paperwork to say what certificate covered what.

I know the original hob in my mothers house was an induction hob, and the wiring was installed with a 32 amp RCBO, but the induction hob raised questions as if suitable with mother pace maker, and also the display could not be seen at the angle of ones eyes to the hob when sitting in a wheel chair, so it was changed to a halogen domino hob which only needed a 16 amp supply, so the RCBO was changed to 16 amp. There was nothing on the paperwork to say this had happened, and if the new owners wanted to swap back to a 4 ring hob, their only way to find out would be to ask me or the installer.

We can assume when we see 6 mm² cable that we can fit a 32 amp RCBO, but it that good enough? For all we know the 6 mm² could be because the cable goes through thick insulation so reference method 103# so 23.5 amp limit. With 4 mm² a 17.5 amp limit and I have seen nothing on the installation certificated to say what the worst reference method is.

So it is only future proof if the installation certificate includes the installation method.

thats the thing, i would ideally want to run 2x 6mm T&E's from say 16A rcbo but that final termination is getting me ?
 
Well, you are rather over egging the pudding but, if you REALLY want to have 6mm² cables then I would finish those on cooker connection plates. Via “cooker” isolation switches (if you feel you want these). Then you can cable directly to your hardwired oven and swop the connector plate for a single socket for the plug in one.
Why only a 16A RCBO on 6mm² cables though?
 
What final protection?

You could go 32a RCBO, 6mm2 cable, 13 amp switched fused spur

or

32a RCBO, 6mm2 cable, 50 amp switch, 13 amp unswitched fused spur

or

16a RCBO, 6mm2 cable, 20 amp switch (or 13 amp switched fused spur)
 
What final protection?

You could go 32a RCBO, 6mm2 cable, 13 amp switched fused spur

or

32a RCBO, 6mm2 cable, 50 amp switch, 13 amp unswitched fused spur

or

16a RCBO, 6mm2 cable, 20 amp switch (or 13 amp switched fused spur)
What about the oven which needs to be hard wired would a 13amp fused outlet be able to handle it ?
 

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