@light*plus: The problem with European HPS lamps on CWA ballasts, is because HPS lamps suffer from voltage rise during life, which can allow CWA ballasts to run them at very high currents.
Dor123, this is the quotation I got from silverliner (Dave) regarding running European high pressure sodium lamps on CWA ballasts:
You can run European HPS lamps on USA ballasts just fine, lol. All HPS lamps have voltage rise over life. Dor123 was referring to HPS retrofit lamps for
mercury ballasts. There shouldn’t be issues running European standard HPS lamps in 250w and up because they share the same electrical values. Lower wattage HPS lamps are different as ours are low voltage types designed for 120v chokes. Theirs are more like our low wattage MH lamps.