Thanks heaps for the info so far
All my points are on a RCD, and am very particular about unplugging.
Dunno if another angle will help at all
The black PSU is silver PSU
+12 +5
-5 GND
GND GND
+5 +12
+5 NC
FG FG
AC ~
AC ~
GND's are connected
+5's are connected
FG's are connected
AC's to ~ are connected
there is no connection between the +12, and this would be due to the fact that there is no +12 on the black PSU - spot on Firepower - it seems the silver one is an add on.
When i took the FG off the black PSU there was no reading for resistance (or continuity) between FG and GND - same on the silver one. Resistance between the FG and the earth screws was around 0.5 ohm
