Wiring an electric cooker and electric hob

[Leon_marsh]

Is it possible to run an electric single oven (~2.5kW) and electric hob (~6kW) from one single 4mm 30A cable direct from the consumer unit on a radial circuit of ~20m in length?

If not, my DIY book with the new regulations suggests I can run a small oven <3kW off a 13A socket or preferably fused control unit from the ringmain. If this is the case then the hob could use the 4mm dedicated radial...?

Thanks in advance.

 

[JohnD]

4mm cable installed in a wall usually has a capacity of 27Amps (there are variations depending on where and how it is installed) so you may need a new cable run.

6000W is about 26 Amps so is OK for the hob except that the fuse is above the cable capacity. I think, if it is already installed, many people would leave it until the installation needs to be upgraded. You might not be able to supply a large electric cooker (oven and rings) from it.

8500W is about 37 Amps

6mm cable has a capacity of 35A
10mm has a capacity of 47A

In your position I would be inclined to run a 6mm cable, protected by a 32A MCB. Then the cable will be safe from overload and it will have ample capacity for the hob.

It would be possible to run the oven of this as well as the hob, but there would be a risk of overloads tripping the MCB when you are cooking on all elements (this typically happens when cooking the Christmas dinner).

It would be preferable to supply the oven from a separate socket or FCU. If you want a separate oven circuit, you could run a 2.5mm radial protected at 20A, which would be adequate for most double ovens (should you get one later). If the downstairs socket ring is not heavily loaded a single oven can be supplied off that, but not a double.