Grounding Question

Hi,
Was hoping to get some advice on grounding. I just started modifying an old PC case to house my...

1. Computer (Motherboard, PSU, CDROM, HDD)
2. Stepper Electronics (G540, PSU)
to clarify one PSU will power the computer and the other the driver.

Will I need to isolate the two PSU's? Or is this a bad idea altogether?
Somewhere I saw that someone had done the samething but I can't find it now.

I have a power jack similar to this. My thought was to mount the jack in the back of the case. Then run the "G" and "N" wires straight to the driver PSU and the "L" to a ON/OFF switch in the front of the case.

Here is where I get confused. The case is grounded by the computers PSU right? If I mount the driver's PSU to the case is it now grounded? Will having them both grounded cause issues?

Thanks ahead of time for any guidance.

The computer's power supply is likely grounded to the computer chassis on both the AC line input side and on the DC output side.

The driver's power supply chassis is probably also directly connected to the G terminal on the AC line input. So by bolting the power supply chassis to the PC case chassis, you will be sharing that ground connection between the two power supplies. That ground is there for protection against possibly-dangerous wiring faults with the AC line. I do not expect sharing those grounds to cause any issues for you.

The negative terminal of the driver's power supply can be kept isolated from the chassis ground. It goes to the G540's negative power input (and to the limit switches).

doorknob,
Thanks for your reply. I was hoping I wouldn't have to isolate the driver PSU from the pc's case.

I really appreciate places like CNCZone. All the knowledge and great people that can be found here is just awesome.

Thanks again.