> >I'm figuring on 40KV with a 10KV transformer, am I safe? I'm planning on >four parallel strings of four in a series. The estimated puncture voltage >for the thickness of the glass is 10KV. You are probably safe without any in series-- in my opinion. Glass has one of the highest breakdown voltages, I doubt that with a 10 kv transformer you would punch through glass of any common thickness.