Installing induction hob+electric oven...separate circuits or same?

[les24preludes]

New kitchen - induction hob at 7.4kW (32amp) and oven at 3.6kW (16amp) max ratings. Existing outlets are:
1. 45amp fused cooker circuit
2. fused socket off ring main (32A fuse)

Can both oven and hob be connected off the one 45amp cooker circuit? That's right up to the maximum.

Or can the oven be connected to the ring main?

Or does the oven require its own circuit - that would be an extra installation and need rewiring to the fuse box.

 

[les24preludes]

With diversity taken in to account the load comes to roughly 21A. How is the 6mm cable cooker supply installed?

As I was saying above, there are 2 supplies under the worktop

1. Cooker supply, as described, 45 amp fuse in fusebox but looks like 6mm 32 amp supply with a switch and neon above the worktop, so suitable for hob only
2. Fused and switched supply off the ring mains which may or may not be suitable for a 16 amp 3.6kW (max) oven

 

[westward10]

Although it is almost certainly 6.0 it wouldn't be impossible for it to be 4.0.

 

[les24preludes]

Not necessarily...How is the 6mm installed. Does the route encounter any insulation?

You're talking about the "cooker" supply here? What do you mean by "does the route encounter any insulation"?

 

[westward10]

Are you talking about the final connection to the cooket or the cable from the board.

 

[Leesparkykent]

You're talking about the "cooker" supply here? What do you mean by "does the route encounter any insulation"?

How a cable is installed is called the installation method. The installation method is a factor that determines the current carrying capacity of the cable. One of the worst installation methods with regards to current carrying capacity is when the cable is run through or touching insulation. Do you know how your 6mm oven supply is installed so we can get a better picture of the current carrying capacity of the cable to aid further advice?

 

[les24preludes]

How a cable is installed is called the installation method. The installation method is a factor that determines the current carrying capacity of the cable. One of the worst installation methods with regards to current carrying capacity is when the cable is run through or touching insulation. Do you know how your 6mm oven supply is installed so we can get a better picture of the current carrying capacity of the cable to aid further advice?

You're talking about the existing "cooker" supply here? It will be used for the induction hob, not the oven. From the fuse box (45 amp fuse) there is about 8 metres of twin and earth going to the switch with neon. About 4 metres goes along brick wall and 4 metres in stud wall. Then from the switch above the worktop, about 1.3 metres to the junction box under the worktop. Is this what you want to know or can I gave you any more info?

This is all really helpful, guys.

 

[Dave OCD]

Good points. The 45 amp circuit comes from the fuse box, where there's a 45 amp fuse, into a wall mounted switch with neon (no fuse). The wiring here is 5mm OD overall including insulation - I haven't looked up specifications yet to determine if this is 6mm or 10mm. Should be 10mm, so I hope that's right. The same diameter wiring goes down to what looks like a 45 amp junction box on the wall under the worktop. This is a usual single size junction box, i.e. 850x850mm.

If the supply were split into hob and oven, I'm thinking it would need a larger 3-way junction box. I'm expecting the 5mm OD cable to be 10mm, and from there it would go to a 6mm for hob and 2.5mm for oven. The butyl cable to the hob is 15mm OD including insulation - pretty solid.

That's some junction box, probably bigger than the frontal area of an oven. I think you may mean 85mm x 85mm...

 

[Leesparkykent]

You're talking about the existing "cooker" supply here? It will be used for the induction hob, not the oven. From the fuse box (45 amp fuse) there is about 8 metres of twin and earth going to the switch with neon. About 4 metres goes along brick wall and 4 metres in stud wall. Then from the switch above the worktop, about 1.3 metres to the junction box under the worktop. Is this what you want to know or can I gave you any more info?

This is all really helpful, guys.

Sorry I thought you wanted to know if the existing supply was adequate for both the oven and hob? The 4 meters that goes through a stud wall do you know if its packed with insulation?

 

[Octopus]

Have you got the oven? does it come with a cable? and if so does it have a plug attached?

 

[telectrix]

Looked again, and you're right - the earth wire is solid. Pretty much confirms that the "cooker" supply is 6mm, so 32 amp. So hob only.

NO. unless the 6mm cable is run through insulation, it will handle both hob and oven with ease.

 

[Dave OCD]

On the other hand if it's easy to run a seperate oven supply and ideally via separate RCDs or RCBOs you have the advantage of still having one cooking appliance operational should one develop a fault and 'trip' the RCD or OCPD.

 

[telectrix]

On the other hand if it's easy to run a seperate oven supply and ideally via separate RCDs or RCBOs you have the advantage of still having one cooking appliance operational should one develop a fault and 'trip' the RCD or OCPD.

always the negative waves, moriarty, always the negative waves. woof, woof.

 

[Dave OCD]

always the negative waves, moriarty, always the negative waves. woof, woof.

Are you p155ed ? I thought my post was positive, you'd want things designed as well as possible in your own house ?

 

[telectrix]

he cast out his hook and got a bite within seconds,

 

[Midwest]

How time flies.