HI from Ken, G4KIR,

Why not just borrow ( if you don't own one that is ) an Electricians
insulation tester, known over here in the UK as a "MEGGER".
These units can produce around 250-1000volts (if you can get hold of a good
one).
This will test your insulation no problem.

Hope this helps, cheers, ken, G4KIR.

"raypsi" wrote in message
...
I built my own 7.5VACT 21amp filament xformer. I needed to supply
-500VDC
73
n8zu