I've got a switch mode power supply and I have a question on the grounding of the PCB. Documentation on the PSU can be found here:
On the back of the pcb you can see 2 of the 4 screws holes with a star. I assume that these are meant to be screwed into a chassis where these screw holes will connect to chassis ground.
A schematic representation can be seen here :
M1 (the one on the AC side of the board is called "M1 - Safety Ground". The other one (on the DC side, not named but labelled M2) is not electrically connected to M1.
According to the documentation it states :
M1 is safety ground. For better EMC performance, please secure an electrical connection between M1,M2 and chassis grounding.
The chassis where I will be hosting this power supply has the green/yellow wires (ground) hooked up to the chassis.
So the questions :
- Do I connect 2 wires from M1 and M2 to this green/yellow wire ? I don't have any corresponding screw holes so I was thinking about soldering a wire on M1 and on M2 and hooking them up to the green/yellow wire you see in the picture above.
- Perhaps a stupid question, but if it's always the end-goal to have these 2 grounds connected (will be the case if you screw it in), then why aren't these electrically connected in the first place ?
The PSU would be attached to the chassis like this (using a single screw as the others don't correspond with the ones in the chassis) :