I'm pretty sure I got a bad PSU to start with. From the beginning it sounded like it was going to explode. I will measure the overall current when my new PSU arrive. I'm guessing that the consumption is pretty close to 30 amps when the bed and extruder are on.

I bought a 12v 75 amps server PSU to be in the safe side. Most of the big 3d printers use 24v..