Installing new ceramic hob and double oven

[sarav]

We have bought an electric double oven and seperate ceramic hob to replace the the old seperate oven and hot plate hob.

The new oven needs 5.2kw and the hob needs 6.3kw, which I understand means 22amps and 27 amps respectively without taking diversity into account.

I have an existing 30amp socket (used by the old cooker), which I can connect one of the new items to (probably the hob as its juicier).

However I am now a bit stuck on what to connect the oven to? I have been told by an electrician friend that I can run a supply off one of the existing power sockets to feed the oven - however I'm not certain that this is the right advice. I know that in theory my total supply requirement is 49amps - but I fail to see how that can be split between two connections and two appliances (that is how he explained it).

Any help/advice gratefully received.

thanks

 

[Steve]

In an ideal world you'd have two 32A circuits.

However, there shouldn't be a problem running them both off the one circuit, since neither will ever be drawing the full load current all the time.

dual cooker outlet plate.

 

[ColJack]

what size cable do you have installed, it may be possible to upgrade the breaker to something a little meatier if the wiring will allow..

 

[ericmark]

Be aware little to no diversity can be allowed with Induction hobs due to the "Boost" function. But any other hob it is allowed.

 

[Notaspark]

Be aware little to no diversity can be allowed with Induction hobs due to the "Boost" function. But any other hob it is allowed.

Citation required please.

 

[slup]

Be aware little to no diversity can be allowed with Induction hobs due to the "Boost" function. But any other hob it is allowed.

If you have a conventional hob with four 2KW heating zones and you put all four of them on, the hob will draw 8KW until the individual thermostats kicked in.

An induction hob does exactly the same thing but manages it more intelligently. If you had the same imaginary four 2KW heating zones and you put them all on full power (not boost), the hob would draw 8KW. If you switch one of them to boost, all it does is rob power from the other zone on the same controller - so one of your zones would drop to 1KW and one would up to 3KW. Total power consumption remains the same.

Also, when you use a conventional hob, the elements are switched on and off at full power for several seconds or minutes at a time in order to regulate the temperature. The induction hob achieves this by rapidly switching on and off.

Given that an induction hob will heat pans to the desired heat far quicker than a ceramic hob, the overall power consumption over time will be lower with the induction hob.

I don't really understand how any of this affects diversity. I'm not arguing, just curious!

Steve

 

[davelx]

I was unclear about this too, and in fact it depends on the design of the hob. I found this helped:

http://theinductionsite.com/electricity.shtml

http://theinductionsite.com/how-induction-works.shtml

Bottom line is that with SOME induction hobs, a single ring with boost turned on can draw the FULL POWER rating of the hob for 10 minutes or so continuously, in order to fast boil, say, a large pan of cold water. So the circuit has to be able to handle that.

 

[slup]

... and that's where diversity comes in then ... you could put all four rings on full on a conventional hob and it would draw the same amount of power as the induction hob with one zone on full power. The difference being that you are less likely to do that than you are with the induction hob.

So it's more about usage patterns than electrical characteristics?

Incidentally, all the induction hobs I've come across are split into sections with the boost power being shared between either the two left hand or rearmost zones. I've got a 5 zone DeDeitrich one which is in three sections. You can have one of the left hand zones, the middle zone and one of the right hand zones in boost mode at any one time. It then backs the power down on the other zones to '7' out of '15'. If you try to advance either of the remaining power settings above '7', it kills 'boost' on the associated zone.