Diversity: Having elec oven AND Induction hob from cooker sw

[garrymum]

Hi

I read somewhere about diversity, where someone had an induction hob and his electric oven plugged into a double socket which was fed from his cooker plate (the dedicated cooked circuit from his CU). Even though the theoretical total AMPS was way above the 30A of the circuit, because of "diversity" this would be fine.

Is this correct?

I have an induction hob to install, rated at 6.6kw (about 29 amps) and also an oven, rated at 2.15kw (about 10 amps)

At the moment, I have a double socket in one of the kitchen cupboard which the oven is plugged into along with the current gas hob (for the electric igniter).

Any advice would be greatly appreciated.

Thank you.

 

[ericmark]

Read the manufactures instructions on the induction hob as because of the boost often included the induction hob may have no diversity and may need whole of supply. It may also require a maximum size of MCB/Fuse as well as minimum size so what ever supply it may need to be devoted to induction hob.

The 13A socket will not supply the hob and the oven should have a fused connection unit rather than plug and socket. Sometimes a plug and socket is used to allow the oven to be removed for maintenance but I would not recommend the standard 13A type as they are not really good enough for continuous supply of 2Kw and above.

If the circuit is dedicated to oven and hob it may be enough at 30A but you can't use ring main. Because oven and hob are built in the manufactures can require external protection it does not have to be built in. So read instructions. May require semi-conductor fuses.

Not really a DIY job. And if new circuit is required then to DIY will cost more than getting a reg electrician because of LABC charges.

 

[DCC]

Well unless I misread it sounds like you haven't got a suitable supply for your new hob, you need a dedicated circuit large enough for the hob. The oven can be connected to the existing socket assuming it has a plug.

Diversity is applied over a wide area not a single device ... e.g. if you plugged a 13 amp fan heater into every socket in your house you'd expect fuses to start blowing but diversity says its unreasonable to expect every socket to be supplying its maximum rated current. You shouldn't really apply it to a hob because its very likely there will be occasions when all the rings will be on high (christmas anyone?). Induction hobs are worse because the way they operate at low power settings is to pulse the full power on and off briefly.

In short, no, you need a dedicated supply for the hob.

Edit: Seems I was typing too slowly.

 

[ericmark]

All hobs of old design switch on and off. But induction hobs can alter power and often are paired so when pair is used the power is shared between pair or if only one is used extra power is feed to the single ring. (Referred to as boost) As a result in the main the induction hob takes full supply for longer time than old simmerstat controls so diversity can't be applied as it was with old type cookers.

Not all induction hobs are the same so it is very important to read manufactures instructions and follow.

Fuses and MCB's trip or blow at rated current due to heat which is OK as they are designed to stop cable overheating. To heat takes time so an overload of a few seconds will not open the circuit so because the old cooker would start switching the heat on and off before the fuse or MCB got hot enough to open it could be supplied with a unit smaller than total spot demand. This is not the case with induction hobs plus they often require fans to cool them so should the supply fail they may be damaged due to over heating.

Hence again read manufactures instructions.

 

[garrymum]

Thanks all for all the replies.

Will have a look at the instructions. Still unsure whether we are keeping the induction hob or sell it.

We bought it months ago, a Hotpoint ET6124X. Obviously never been used.

Probably end up putting it on ebay!!!!

Thanks again for the advice.

 

[ericmark]

I see nothing wring with Hotpoint ET6124X other than touch controls. I have been told that water spillage onto touch controls can mess things up. But that is only hear say may be wrong.

Most hobs will need a dedicated supply so no real so no real difference. I like the idea of induction hob but I am waiting for my mothers to be fitted first before I buy one.