[volt-nuts] 5200a extender

[Mark Sims]

The tightest clearances are where an etch runs between two pin on the ribbon cable connector.  The connector pin are spaced 0.10" apart.  The pads are .060" octagonal pads so edge-to-edge is a .04" gap.  A .016" trace runs in that gap.  So there is a .012" clearance between the pad edge and trace.  Worse case would be 300V bridging that gap,  but the Fluke edge connectors are set up so that (I think) the highest potential difference is 190V (between the +/-190V lines and GND.   There is a possibility of +300V and a signal called /LIMIT.  
The layout/pad sizes could be tweaked some and that .012" gap could be increased to maybe .020"   A board layout that didn't run etches between pads is not practical and/or would require a board size that exceeds that permitted by my CAD program (or requires a $1700+ upgrade).  So what's the safe arc-over distance for 300V on a G10 circuit board?
The ATTEN,  PWR AMPL,  and PWR SPLY boards all have the high voltages on them... and they aren't on the same pins...