Double ovens and manufacturers instructions

[Spikenaylor]

New kitchen install

Integrated Double oven unit
Integrated single oven unit
Next to each other

Existing circuit
6mm 32A mcb

New double oven manufacturers instruction
40A fuse hard wired
New single oven manufacturers instruction
16A fuse hard wired

Existing cable too short for new isolator position, needs to come out and be replaced

So
According to manufacturers instructions

I need 10mm cable (for the 40A fuse) regardless of diversity

Anyone come across this and do you abide by manufacturers instructions or do you diversity and cable calc to size cable

So two dedicated circuits to two isolator
Then how to route cables to ccu

Do you go down below worktop and the over and up to ccu or space permitting go horizontal through one of the isolators

Or is there a neat way for two isolators to two ccu

Any Recommendations on best way of connection

Do I include the option for if the single oven gets upgraded to another double oven


Not bothered about hob as this is going in island on another dedicated circuit

Any advice greatly received

Many thanks for looking

 

[Octopus]

whats the ratings of the ovens?

10mm seems well OTT

 

[Des 56]

After deciding which cable to use, the existing 6mm or a new 10mm

Check the loading and maybe you can fit one isolator for both ovens feeding a dual accessory box, a snout and a fused spur,route the cables run to suit requirements of safe zoning

 

[Spikenaylor]

Murdoch
The oven details provided was 10.8Kw and 40A fuse, but can I re-find the oven details, can i heck, will look later
diversity pulls it down to 21A ( i always use 230V)

but doesnt BS7671 imply the requirement is to abide by Manufacturers instructions which states 40A fuse!

 

[Taylortwocities]

I need 10mm cable (for the 40A fuse)

Why? Is the cable bedded in thermal insulation, or something?
6mm on 40A is generally OK.

but doesnt BS7671 imply the requirement is to abide by Manufacturers instructions

I don't think it says it that strong. IIRC it says something like taking the MIs into account.

Really need the actual rating of both ovens before commenting further.

 

[Midwest]

Manufacturers instructions should be taken into account. Diversity can be applied. How each oven operating controls should also be taken into account, i.e. a simple single oven usually has a control knob, that only allows the user to operate one or two elements at a time. Your oven may operate otherwise.

Some manufactures state a total load, and a maximum usable load.

What is the oven make & model; you could try asking the manufacturer for max load advice, but I do find them a bit hit & miss. I make your oven just over 35A (using 230V), so you would have to provide a 40A supply for that.

 

[Spikenaylor]

right, found the ovens. this may be subject to change!!


Going off the AO.com website for electrical details


Scenario 1

double oven 6.3KW fuse 32Amp - diversity 15.22A

single oven 2.99KW 13A Plug - diversity 10.9A

diversity for both together 19.12A


so I would use 6mm (covering future)

32A MCB to isolator switch fed to FCU and then to socket for single oven and also to CCU for double oven

reference method 100 or even 101 would be sufficient for 6mm


Scenario 2


replace the single oven with double oven of the same


again 32A MCB 6mm to isolator to dual CCU

2 double ovens 6.3KW fuse 32Amp - diversity 23.43A

reference method 100 or even 101 would be sufficient for 6mm


could leave space when chasing to upgrade to 10mm if required at a later date, but suspect ovens becoming more efficient


this may need two circuits as close to current limits of 6mm or just fit 10mm for this scenario


Scenario 3

add warming drawer to single oven

double oven 6.3KW fuse 32Amp

single oven 2.99KW 13A Plug

warming drawer fused plug

diversity for ovens 19.12A

lets add on 5A to use a socket on the circuit 24.12A



6mm to isolator switch fed to FCU and then to double socket for single oven and warming drawer and also to CCU for double oven.


would you guys now connect the warming drawer to the cooker circuit or would that be feed off ring



still not sure about the best method to cover this, 10mm, two 6mm circuits etc

 

[Midwest]

Is this your own installation OP, or are you doing it for someone. Until the client has decided upon what appliances he/she wants, you can't really plan your installation, unless you just drag in a couple of 6/10mm and take what comes?

On diversity; I do not apply it to the combined appliances, but just to each appliance. Some might not agree with that, but in my opinion, thats how it should be.

 

[Spikenaylor]

this is for my own installation, but not come up against this scenario before, the double and single oven is the current plan, but so is a 2 double ovens , and or single and warming drawer.

just putting in 10mm then would accommodate most scenarios for two ovens side by side

how would you connect a warming drawer, to the cooker circuit or to the ring?

 

[Midwest]

this is for my own installation, but not come up against this scenario before, the double and single oven is the current plan, but so is a 2 double ovens , and or single and warming drawer.

just putting in 10mm then would accommodate most scenarios for two ovens side by side

how would you connect a warming drawer, to the cooker circuit or to the ring?

Unless the two ovens are side by side, I would provide two separate circuits, just easier at the appliance end, regardless of cable size etc.

The warming draw, is normally low wattage? Have you decided on other circuits for your kitchen?

 

[Taylortwocities]

Oh dear

how would you connect a warming drawer, to the cooker circuit or to the ring?

Here we go again. That's a bit like asking "how fast will my car go?"
What is the power requirement of the warming drawer?

 

[Octopus]

so you've got 2 ovens and a warming drawer

I would be running in 2 dedicated circuits ...........