Induction hob and oven query ?

[182_blue]

We are having our kitchen re modelled and have just found that we have a 45amp switch with a 10mm cable under the present gas hob (this is not over the oven and is at the other side of the kitchen), the oven has the same cable size and when you turn the oven off at the consumer unit it turns off the supply to where the hob would be also, both the hob and oven have an independent switch, the fuse in the consumer unit is 32a for the cooker/hob circuit.

The plan was to fit a gas hob but a kitchen fitter has mentioned that we could have an induction hob instead, now my question is will my current set up be OK to just add the induction hob ?

The hob we like is a Neff running at 7.9kw and the present oven is also a Neff (double) oven running at 5.7kw.

TIA

 

[JohnW2]

The plan was to fit a gas hob but a kitchen fitter has mentioned that we could have an induction hob instead, now my question is will my current set up be OK to just add the induction hob ? ... The hob we like is a Neff running at 7.9kw and the present oven is also a Neff (double) oven running at 5.7kw.

If such is what you've got, a 32A circuit (32A fuse/breaker in the CU) wired with 10mm² cable would be plenty adequate for running both those appliances. You may want to get an electrician to confirm that the cable is what you think it is.

Kind Regards, John

 

[182_blue]

The plan was to fit a gas hob but a kitchen fitter has mentioned that we could have an induction hob instead, now my question is will my current set up be OK to just add the induction hob ? ... The hob we like is a Neff running at 7.9kw and the present oven is also a Neff (double) oven running at 5.7kw.

If such is what you've got, a 32A circuit (32A fuse/breaker in the CU) wired with 10mm² cable would be plenty adequate for running both those appliances. You may want to get an electrician to confirm that the cable is what you think it is.

Kind Regards, John

Thanks for the reply.

The kitchen fitter (who we are not using now) was getting somebody to do the electrics as he didnt have the relevant qualifications, i was just wondering as i need to order the appliances soon, I'm happy with the gas hob but my wife has fallen in love with one of these Neff flex hobs!.

 

[182_blue]

How do i tell if i have 10mm2 cable ?

 

[JohnW2]

How do i tell if i have 10mm2 cable ?

I suppose I might equally ask you what made you think that it was 10mm²

What are the approximate external dimensions (over the white or grey outer sheath)?

To be frank, 6mm² would be more than adequate for a 32A cooker circuit and, in many/most situations, even 4mm² would be adequate.

Kind Regards, John

 

[ban-all-sheds]

How do i tell if i have 10mm2 cable ?

//www.diynot.com/wiki/electrics:flatpvccables

 

[182_blue]

How do i tell if i have 10mm2 cable ?

I suppose I might equally ask you what made you think that it was 10mm²

What are the approximate external dimensions (over the white or grey outer sheath)?

To be frank, 6mm² would be more than adequate for a 32A cooker circuit and, in many/most situations, even 4mm² would be adequate.

Kind Regards, John

Haha, i could swear i had written it above, anyhow the now sacked kitchen fitter told me LOL, i will measure it in a short while after i pick my young one up, thanks again though.

 

[182_blue]

Ok, the cable appears to be 14mm x 8mm !

 

[JohnW2]

Ok, the cable appears to be 14mm x 8mm !

That sounds like 6mm², which typically (it varies) has external dimensions of about 13.5mm x 7mm (10mm ² is typically about 17.1mm x 10mm). If that's the case then, as I said, that should be fine for a 32A cooker circuit (which typically are wired in 6mm²).

Kind Regards, John

 

[182_blue]

Ok, the cable appears to be 14mm x 8mm !

That sounds like 6mm², which typically (it varies) has external dimensions of about 13.5mm x 7mm (10mm ² is typically about 17.1mm x 10mm). If that's the case then, as I said, that should be fine for a 32A cooker circuit (which typically are wired in 6mm²).

Kind Regards, John

OK, so just so i am clear, the cable i have should be fine to run both the induction how at 7.2KW and a double oven at 5.6kw ?

 

[JohnW2]

OK, so just so i am clear, the cable i have should be fine to run both the induction how at 7.2KW and a double oven at 5.6kw ?

Yep, more than adequate. The limiting factor with your setup is actually the MCB (32A), rather than the cable (which is fine for more than 32A). Assuming the 12.8kW total you mention relates to 240V (they virtually always do), that amounts to a maximum current (at 240V) of about 53.3A. However, for cooking appliances, one is allowed to apply a 'diversity correction', that takes into account the fact that not all elements will usually be drawing current simultaneously. The formula for that is "the first 10A plus 0.3 times the rest" - which, in your case, would be 10A + (0.3 x 43.3A), which is about 23A, well under the 32A capacity of your circuit.

Kind Regards, John

 

[182_blue]

OK, so just so i am clear, the cable i have should be fine to run both the induction how at 7.2KW and a double oven at 5.6kw ?

Yep, more than adequate. The limiting factor with your setup is actually the MCB (32A), rather than the cable (which is fine for more than 32A). Assuming the 12.8kW total you mention relates to 240V (they virtually always do), that amounts to a maximum current (at 240V) of about 53.3A. However, for cooking appliances, one is allowed to apply a 'diversity correction', that takes into account the fact that not all elements will usually be drawing current simultaneously. The formula for that is "the first 10A plus 0.3 times the rest" - which, in your case, would be 10A + (0.3 x 43.3A), which is about 23A, well under the 32A capacity of your circuit.

Kind Regards, John

OK, thanks for your help, just one more question, currently we have just a fuse box that feeds the igniter for the current gas hob, what type of box should i buy to replace this ?

This is the box

 

[JohnW2]

OK, thanks for your help, just one more question, currently we have just a fuse box that feeds the igniter for the current gas hob, what type of box should i buy to replace this ?

Your electrician will know what's required - probably a 'cooker control unit' (big switch, perhaps with a socket) and a 'dual output cooker plate'.

Kind Regards, John

 

[ban-all-sheds]

Your electrician will know what's required

And hopefully he'll reterminate these a little better...

 

[ericmark]

He may use a cooker connection unit or he may go direct into the isolator. He will need to replace the fuse connection unit.

My mothers kitchen was wired for oven and induction hob but when the induction was swapped for a domino halogen the cooker connection unit was swapped for a fuse connection unit. They both use same back box so an easy swap.

This is why we use electricians rather than DIY as an electrician can recognise what he has in front of him. Easy swap CCU to FCU but reverse need checking more carefully to ensure correct cable sizes.