What kind of wires do you need for the oven in 4000W?
3 to the electric wire, thicker ~ you buy when the seller will recommend to you ~!
4 square copper wire, you can open 32A.
220V, 4KW electric oven, current 18A total switch, it is better to use leakage protector 220V, 25-30A, power line can use 1.76 square millimeter copper wire.