Hob and Oven

[aryl]

Apologies if repeating a subject that seems quite frequent in this forum but I cannot quite put it all together.

I need some help to understand what is needed for connecting an electrical hob and oven. I have the hob but still need to buy an oven.

My hob is labeled 7.3kW and currently connected on a dedicated circuit. From the Consumer Unit where there is a 45A fuse a 6mm T&E cable goes to a 45A DP Switch with a 13A Socket. The Hob is then connected from there. Overall the cable is no more than 10m.

So my questions are,

1. Can I connect the Oven directly to this circuit with a cable into the same 45A DP switch?
2. What is the highest power usage my oven can have for this circuit combined with my Hob.
3. Can I connect the Oven to a “normal” circuit i.e. not the dedicated Hob circuit?

Thanks.

 

[echoes]

Assuming that the 6 mm² is installed in such a way that a 45A breaker is adequately protecting it (i.e. clipped direct / in plaster / no trunking) then:

1) An electric oven can be connected to the same circuit; using a dual cooker outlet plate between the 45A switch and the appliances.

2) Diversity calcs for cooking appliances give 25kW of appliances requiring a 45 A supply. Even if the circuit was 32 A, you can connect up to 15 kW, giving room for 7.7 kW of oven + 7.3 kW of hob, and that's still an awful lot of oven.
http://www.tlc-direct.co.uk/Book/6.5.2.htm

3) You could have a new dedicated circuit for the oven installed. The oven should not be connected to a general-purpose socket circuit.

In short, your 45 A circuit is more than ample to supply both an electric hob and oven in normal domestic use. Refer to the oven's instructions for its recommended connection.

 

[aryl]

Thanks for the reply echoes!

So, to conclude, I should keep the 6mm T&E to the 45A DP Switch and from there run a 6mm cable to a dual cooker outlet plate and from there two separate 6mm for hob and oven.

I believe the 6mm run in plaster or the cavity wall from the CU for about 1.5m up to the 1st floor then underneath the floors to the kitchen. Then in the kitchen 1.5m down to the DP Switch in wall plaster (this bit is not yet in the wall plaster, when it is done is it better to run it in a duct? ). I plan to run a new 6mm cable from DP Switch to the dual cooker outlet plate in the wall plaster.

Will this be OK?

 

[echoes]

So, to conclude, I should keep the 6mm T&E to the 45A DP Switch and from there run a 6mm cable to a dual cooker outlet plate and from there two separate 6mm for hob and oven.

Yes

(this bit is not yet in the wall plaster, when it is done is it better to run it in a duct? )

No - when protecting 6 mm² cable with a 45 A breaker it must be clipped direct. i.e. clipped to wall or buried directly in plaster and be subject to no other derating factors; otherwise it risks overheating. It is only rated at 47 A when installed in this manner.

Also check your cable length is less than the max length of the cable allowed for this configuration. I don't have the handy tables to hand.

I plan to run a new 6mm cable from DP Switch to the dual cooker outlet plate in the wall plaster.

That's OK, but you must ensure that the cable is installed in the safe zones created by the cooker outlet plate and the cooker switch. Absolutley no diagonals.