Lets assume in European Union, that I have two power supplies, that each have 3 terminals. One marked +, second - and third GND. I assume that GND is connected to the protective earth of AC power cord and that PE can be disconnected from - on one of the power supplies. Is it possible to connect them both with safety against electric shock maintained?
I imagine that I leave GND and - connected on the first supply, and I'll disconnect GND from - on the second supply, then connect GND of both of them to prevent shock from touching the chasis of the second supply. Next I connect + of the first supply to - of the second supply and take output voltage from + of the second supply. Lastly I plug them to the AC outlet and power them on.
EDIT: Could someone please elaborate on how does connecting GND of my circuit on bare PCB to protective earth protect me from electric shock?