Two cookers on single circuit

I have one single oven connected on a radial circuit (only one cable comes out of consumer unit), protected by a 32A MCB in consumer unit. I think the cable is 4mm (it measures 14mm when laid flat and measured edge to edge with a rule). This cooker is the only appliance on the circuit and it is currently isolated by a Cooker Control Switch with a combined 13A socket.

I want to replace the old cooker with a new cooker rated at 2.8Kw and a new Oven/Microwave combination unit rated at 3.6Kw. Both appliances have cable which needs connecting to a permanent socket (ie no 3pin plugs on ends of cables).

I have a couple of questions :-

1. Can I supply both appliances from the existing radial circuit, or do I need to upgrade the cable and MCB?

2. If I can supply both appliances from the circuit I assume I cannot have a 13A socket as part of the Cooker Control Switch (as I currently have at the moment)?

3. Do I need two Cooker Control Switches (one for each appliance) or can I use one switch to isolate both appliances?

Your new 2.8kW oven can be plugged into a normal 13A socket outlet (low level behind your kitchen units etc)

Oven Rating / Voltage = Current
2800W / 230V = 12.17A

And your existing 4mm cable will supply your combination unit which is around 15Amps.

I wouldn't recommend supplying both appliances from the one circuit.

I confirmed this morning that the cable is 6mm. I acquired a 2" piece of cable and compared to cable coming from consumer unit and they are the same thickness.

This means

(2800 + 3600) / 230 = 27.8 A

which would work on a 30A circuit.

im always dubious about connecting such low rated quipment directly to a 32A cuircuit

personally i would say go into a cooker control unit as normal but then instead of using a cooker connection unit (sometimes refered to as a cooker outlet plate) hide a small CU with a couple of 16A breakers in a cupboard and connect the cooking appliances to this

Many thanks for your replies Plugwash and il78. I'm still considering what to do about this, but I guess there is an additional piece of information I forgot to mention in my original post.

The new cookers will be sited on the opposite side of the kitchen to the existing cooker. This means the existing 6mm cable will not reach, hence I either have to extend the cable via a JB (not ideal) or replace the cable with either 6mm or 10mm cable.

Replacing the cable would be my preferred option, since I don't like joining cable, but it involves more work (naturally).

Please keep the appends coming and when I finally decide what to do, I'll provide details for others to read.

I would not run two cooking appliances from one 4mm feed.

Technically speaking, you can apply diversity to the total cooking load (do a search for diversity + cooking), but there is a general feeling among sparks that it is best, wherever possible, to allow for the full load current when designing these circuits.

I would use the existing 4mm to feed the microwave and install another larger cable to feed the oven. The reasoning behind this is so that if you ever change the oven for a double, you have the capacity for the higher current consumption built-in to the cable.

In the case of the microwave, you can use a CCU if you want a socket adjacent to it.

Please note that if you decide to supply both appliances from the same circuit, each appliance must be no more than 2m from the isolating switch. If this is not possible, each should have its own isolating switch.

Thank you Securespark.

I've now confirmed that the cable is in fact 6mm, not 4mm. In light of this, would you still give the same advice or do you think there is another alternative here?

I have now installed the two new cookers, so I thought I would append the details, for reference.

I kept the existing 32A MCB in CU (mainly becuase you can't get new ones) and ran a new 10mm cable to a switched Cooker Control Unit. I then ran 10mm cable to a small CU with 2 x 16A MCBs hidden on top of the kitchen cabinets. I then took 6mm cable from each of the MCBs to unswitched CCUs behind each appliance. I then used 6mm cable to connect the applicance into the unswitched CCU.

So far everything seems to be working and nothing has tripped.

seems you went a bit over the top with the cable sizes but thats not goign to cause you any problem