Share the Same Negative Outputs of DC Power Supplies

Thread Starter


Joined Mar 4, 2013

I am working on a project that requires to provide 2 different DC voltage levels (30V and 48V) into 2 channels of one single device. I plan to use 2 DC Voltage Power Supplies, and wonder if I can connect 2 negative outputs from the 2 DC power supplies together so that I only need 3 pins for my device: 30VDC pin, 48VDC pin, and one Negative Pin.

I talked to the power supplier, but they don't have a clear answer for me whether it's possible or not. I am wondering if you have any tips, hints, or suggestions for me when sharing the same negative outputs from multiple DC power supplies.



Joined Nov 30, 2010
Everybody else connects their grounds together, but then you didn't tell us the manufacturer, the model number, what your circuits are, how much current they use, whether they are DC isolated from each other......


Joined Jul 18, 2013
In making grounds common there are two trains of though out there and also it depends on the nature of the separate systems themselves.
One example of confusion that is often done in the hobby CNC world is where a PC port is used to control a mains fed spindle controller, the mistaken idea is that using an opto isolator or other means of turning the spindle on isolates the PC from the spindle, where in fact the PC power supply is connected to earth Gnd and so is the spindle via the grounded neutral, hence no galvanic isolation, just voltage transition.


Joined Oct 15, 2009
Its very common to have a common ground..
Internally to your product that "shouldn't" be an issue provided the wiring/traces can handle the current,etc.....
But I would still allow 4 leads to attach to your product..

There are reasons to tie the ground together.. and reasons not to for "noise immunity",etc... The person designing the product should know what to do and whats needed for their specific situation..