Frickin Ovens!!

Inconspicuous

Lads, I was hoping I could pick your brains if you wouldn't mind.

I was having a read of this thread here:

http://www.boards.ie/vbulletin/showthread.php?t=2057353370

The people were discussing the power needs for running two electric hobs and two ovens. Some of what was said got me thinking of what our own kitchen set up is.

Currently we have a 90cm 5 ring ceramic hob and a large double oven (both ovens about 65ltrs capacity) that run off the same circuit (pretty sure they do as I have the one red kill switch in the kitchen that turns off power to both units.) The house was built in 1997 and I think the woring hasn't changed since then.

We're in the process of putting in a new kitchen and were hoping to replace the hob and the oven with something like these two units:

http://ie.johnlewis.com/store/neff-t41d82x2-induction-hob-black/p819181#default

https://www.fisherpaykel.com/nz/kitchen/cooking-appliances/built-in-ovens/OB60DDEX4/

The double oven is a must as its the only one available with two cavities the same size. The missus has also stated a preference for a 5 ring hob as she does a lot of cooking and regularly would use all the rings on the hob at the same time. Since we're changing I figured it's be better to upgrade to induction.

The problem is that that oven is rated at drawing 27 amps and the hob at about 32 amps (unless I'm way off the mark which is possible since it's been a long time since i was at college studying this sort of thing). Now I haven't checked the circuit at home yet, but I'm pretty sure that this is going to far exceed the circuit.

So my question is.....is it even possible to have these two units in a normal house?

Youngblood.III

Inconspicuous wrote: »

Lads, I was hoping I could pick your brains if you wouldn't mind.

I was having a read of this thread here:

http://www.boards.ie/vbulletin/showthread.php?t=2057353370

The people were discussing the power needs for running two electric hobs and two ovens. Some of what was said got me thinking of what our own kitchen set up is.

Currently we have a 90cm 5 ring ceramic hob and a large double oven (both ovens about 65ltrs capacity) that run off the same circuit (pretty sure they do as I have the one red kill switch in the kitchen that turns off power to both units.) The house was built in 1997 and I think the woring hasn't changed since then.

We're in the process of putting in a new kitchen and were hoping to replace the hob and the oven with something like these two units:

http://ie.johnlewis.com/store/neff-t41d82x2-induction-hob-black/p819181#default

https://www.fisherpaykel.com/nz/kitchen/cooking-appliances/built-in-ovens/OB60DDEX4/

The double oven is a must as its the only one available with two cavities the same size. The missus has also stated a preference for a 5 ring hob as she does a lot of cooking and regularly would use all the rings on the hob at the same time. Since we're changing I figured it's be better to upgrade to induction.

The problem is that that oven is rated at drawing 27 amps and the hob at about 32 amps (unless I'm way off the mark which is possible since it's been a long time since i was at college studying this sort of thing). Now I haven't checked the circuit at home yet, but I'm pretty sure that this is going to far exceed the circuit.

So my question is.....is it even possible to have these two units in a normal house?

Run two separate circuits to their own mcb back to the main board and have two isolator switches....open to correction...

SpaceTime

It's absolutely possible but you'll need to get it installed by an electrician as you're likely going to need extra circuits.

Inconspicuous

SpaceTime wrote: »

It's absolutely possible but you'll need to get it installed by an electrician as you're likely going to need extra circuits.

Glad to know.

We're going to have a sparks on site anyway doing wiring for lighting and the likes so that's no hassle (hopefully). I guess what I was wondering more about was the effect that amount of draw would have on the overall supply coming into the house? Is 59A not an awful lot of power? How much is coming into the house in total?

SpaceTime

Inconspicuous wrote: »

Glad to know.

We're going to have a sparks on site anyway doing wiring for lighting and the likes so that's no hassle (hopefully). I guess what I was wondering more about was the effect that amount of draw would have on the overall supply coming into the house? Is 59A not an awful lot of power? How much is coming into the house in total?

It depends on the house supply. Could be 63amps or 80amps.

You also won't be using the entire lot of cooking facilities at the same time?!

That's he scale of a commercial kitchen that should really be connected to 3 phase.

Youngblood.III

Main fuse is normally 63amp, the cooker/ hob is rated up to 27/32amps for protection not max consumption.
You'll be fine.

Inconspicuous

Lads, thanks for all the advice and sorry for coming back looking for more.

We're in the middle of doing up the kitchen at the moment and have had the sparks on site. I got talking to him about installing an induction hob with a 11kw power rating and an oven with a 6kw rating.

As above, he said that i would need to put in another seperate circuit for hob keeping the oven on the original circuit. However, he was kind of advising against putting in these two units together saying that the current draw of these two devices would push the overall power in the house to its limit.

Now I realise that we will never have all of the inductions zones and the two ovens turned up to their max power settings but at times like christmas we would be using both ovens (probably set at 200C each) and are like to be using all of the zones on the hob though probably not at full power. However given that my electrican is saying that its a risk installing these two units, I'm looking to see if anyone here has had experiences with units like these being used in the real world and whether they do indeed place such a load on the overall power consuption in a house when used on days like Christmas day?

Risteard81

Inconspicuous wrote: »

whether they do indeed place such a load on the overall power consuption in a house when used on days like Christmas day?

No, they don't. Typically what is quoted is Total Connected Load, which cannot actually be simultaneously energised. Furthermore, the loads which are energised will cycle on and off so a domestic cooker circuit will have a much smaller current draw than might be assumed.

Inconspicuous

Risteard81 wrote: »

No, they don't. Typically what is quoted is Total Connected Load, which cannot actually be simultaneously energised. Furthermore, the loads which are energised will cycle on and off so a domestic cooker circuit will have a much smaller current draw than might be assumed.

Thanks Risteard. So in real terms, if i get a second circuit installed i should probably be ok with these two units in the house as it shouldnt have a detrimental effect on the power supply?

And one more quick quextion if you dont mind? I think that the current circuit is probably using 6mm cable. Is this sufficient or should it be upgraded to 10mm?

Thanks again for your help on this

2011

I agree with Risteard81.

Inconspicuous wrote: »

So in real terms, if i get a second circuit installed i should probably be ok with these two units in the house as it shouldnt have a detrimental effect on the power supply?

Generally, yes.

As Risteard81 said the 11kW and 6kW values represent the connected load, not the load that the supply will have to cope with under normal circumstances.

Take the hob for example, this would only be an 11kW load if all rings were turned on to full power at once when the hob is cold. Once each ring achieves the desired temperature it will cycle on and off to maintain that temperature. One ring on would only represent a fraction of that load. The same logic applies to the oven, I guess this is a double oven?

My only concern would be if you have an instantaneous shower (generally around 9kW). This combined with the hob, oven and immersion would be considered a large load for a standard single phase supply.

And one more quick quextion if you dont mind? I think that the current circuit is probably using 6mm cable. Is this sufficient or should it be upgraded to 10mm?

Well spotted.
I would recommend that the electrician wires the hob in at least a 10 sq cable though. Unless the run is particularly long a 6 sq. should be sufficient for the the oven.

Inconspicuous

2011 wrote: »

My only concern would be if you have an instantaneous shower (generally around 9kW). This combined with the hob, oven and immersion would be considered a large load for a standard single phase supply.

Thanks for the info, its very helpful. I do have an eletric shower in the main bathroom but it is virtually never used as we use the shower in our room which runs off the hot water tank. Likewise we virtually never use the immersion either as we have our gas heating set to warm the water at set times in the day.

I think ill just get the sparks to put in the extra circuit and take the plunge. I know it would have been a whole lot easier to get a gas hob but the missus just doesnt like them. Likewise im not a fan of ceramic so induction is the middle ground.

Thanks again for all help and advice, its greatly appreciated