posted on Jul, 16 2012 @ 06:15 AM
reply to post by polarwarrior
Sorry my brain didn't kick in sooner, the picture you posted finally kicked it into gear!,
Single grounds are quite normal on external PSUs as ground is the same for all voltages both negative & positive. If you were to take the computer
power supply apart you'd find all those black wires go back to one large solder pad.
The positive (or negative) voltages are created by regulators inside the PSU's all using the same ground point internally.
Separately running 2 grounds in a PC reduces cable size more than anything.
Here is a typical schematic for what's inside the box:
Typical lazy manufacturer, wouldn't be hard for them just to link the 2 central pins & provide both eh!
edit on 16/7/2012 by supradupradotcom
because: added pic for reference