That depends, but it sounds too small for the application. You may have 30m of wire but how long does the run
need to be? Also, what is the voltage drop tolerance (or what is the voltage of the source and minimum voltage requirements of camera/battery adapter)?
You can play with the numbers yourself using
this calculator to see what gauge you need for any arbitrary cable length. For example, if a 5% voltage drop was tolerable from a 7.5V source, then at 2A, you would need 10mm2 (gauge 8 AWG).
Here's another useful
voltage drop calculator.
If you really need a long run, you might consider running AC closer to the camera and using a shorter DC run.