A fairly typical heated bed presents a 1 ohm load to the power system. That could work out to 12A on the 11A line. A 40W heater on the extruder will pull 3.33 A. Past that you have 6 motors with two windings each. What those 12 windings easy pull depends on a lot of settings and issues. A 30A supply is a better idea than a 20A one.
None of that is what caused the smoke.
Start going through your wiring - there's an error somewhere.
None of that is what caused the smoke.
Start going through your wiring - there's an error somewhere.