Question on grounding PSU

[ChrisLX200]

OK so I'm putting together a PSU consisting of a 48V Mains supply, and a DPS5015. The input to the 48v supply is obviously L & N and whilst there is a third terminal there is no connection from it to anything on the PCB, so the wire from the mains input I will use to ground the chassis. On the output of the 48v supply there is + and - plus a GND terminal, but the input to the DPS5015 just has +IN and -IN. So is this GND left unconnected? I added some pics which may help... Thnx