I have a customer who is testing between two surface conductors
     at 3000 volts. The spacing is at .126". I believe this criteria
     comes from a Bellcore spec. (??? Not sure) When we look up data
     for design in MIL-STD-275 (I believe now it's IPC-D-275) we see 
     that at 3000 volts we should have spacing ~ at .360". 
     (.00012"/volt)(3000 volts)=.36" . (Thanks Steve)
     
     For those of you who are familiar with Bellcore or similar types
     of testing, is this a common test?
     
     Does that spacing appear to be such to open the possibility of
     failure or breakdown?
     
     
     (Being a fabricator, I'm not real versed with tests such as this.)
     
     
     Thanks in advance for any and all responses.
     
     Groovy