I found this question asked before (not exactly this) but the answers were wrong (at least at some level).
So i have two 300W PSU's (different manufacturer so different schematics too). I don't really have any purpose for them but i could use a 24V high amperage (up to 10A) power supply.
So i took one apart, disconnected ground from few screws to chassis (just so that output ground would not be connected to socket/chassis ground). I left ground for all other uses (chassis, grid and some other grounds are all connected). Now i had output ground separated from main ground. I then supplied 12V from other PSU to first PSU's ground. Voltage between PSU1 ground and PSU2 12v then became 24v. 5v became 17, 3.3 became 15.3...
So my question is this: Since all i could find was that this is impossible/very bad to do, it kinda contradicts my findings. The 24V output did hold over 7A load and it seemed to not matter in which pattern i turned them on (i turned "free" PSU first, then the "non-grounded" one second). Is it really that bad to use those PSU's this way? Is it "theoretically bad" or like "100% break down pretty soon"?