Hello everyone, I am in the process of adding a double wall oven to our kitchen,and I was just curious about a few things.OK the cooktop spec plate says 120/208 volts 4.7kw ,not sure but I don't think I worry about the 208 v markings.Correct me if I am wrong. I am in USA. Next it says 120/240 volts 6.3kw which if my math is good would be 26.25 amps. On its own 30 amp breaker. Supplied from the panel with 8 gauge red black white wires. The double oven plate says 120/208 volts 5.10 kw(again I don't think I need to worry about this reading). 120/240 volts 6.3 kw. That should be28.33 amps. Can I run 6 gauge red white black and ground( I think that's 6/3 with ground).Can I run that from the panel to a junction box near the 2 appliances,which they are next to each other, then branch off the 6/3 with 8/3 to each appliance. Another strange thing about the double oven the plate says 3 wire AC only, but it has red black white and green coming out of the conduit. And I will also change to 60 amp breaker if I am allowed to put both on the same circuit. Thank you for any help.

ABSOLUTELY NOT!!
Each appliance requires it's own circuit... with it's own dbl pole breaker. In the US, it's 120 / 240. And re-check your numbers... you have 6.3 KW listed with two different amperages. Ohm's law is an absolute.

Sorry , I miswrote the oven kw it is 6.8. Ok I will put them separate Does the 6/3 wire for the double oven seem like overkill.

Yes. 10 ga. Wire for 30 amp circuits, 8 ga. For 45, 6 ga for 60.
You can use a #8 with a 40 amp breaker for the dbl oven... and you may want to do that for the coktop as well... Doesn't the cooktop and the oven specify what amperage circuit to use?

Neither owners manual states amperage.The manuals are fairly useless.Thank you to everyone for all your help.

Neither owners manual states amperage.The manuals are fairly useless.Thank you for all your help.