Ian,
With regards to the mains isolator. Do you mean switch off the input isolator or the output?
Assuming there are both that is.
I believe this thing is digitally controlled. Has anyone ever worked on one of these? Anyone know where I could find a manual for it?
I found the manual here btw:
http://lit.powerware.com/ll_download...0B4000-ENG.zip
This is for the Powerware Borri 4000 which is apparently the same unit.