I am planning a pcb which is powered by two switching power supplies
The power supplies are mounted in their own metal box and the pcb is mounted in its own metal box. In the lower sketch you can see the layout once more. My question now is whether I should connect the metal box of the pcb and/or the switching power supplies with earth (FG) and/or ground (V-)? The metal box of the switching power supplies is already connected to earth (FG) indirectly over the mounting screws. What would be a reasonable connection when it comes to safety and EMC? Furthermore I looked into the switching power supply datasheet and found that the junction is connected to ground (V-) via a capacitor. Could someone explain me whats the reason for that?