For starters you are using the wrong terms which can be dangerous.

If you have an 11amp breaker for a circuit then you can draw 11amps X 230 Volts = 2530watts

That is for the ENTIRE circuit. You dont want to use the whole amount anyway as you will be tripping the breaker if the voltage varies for any reason. 80% is more than enough. So max safe draw would be 2000watts on the ENTIRE circuit.