As I have been aware of the ANSI code system used throughout North America, I often see North American LG members telling other members that they must only operate HID lamps on their correct ballast. Based on this advice, I often get that feeling that many North American members will say stuff like "Since European HID lamps have no ANSI code on the lamp etch, this means they are NOT COMPATIBLE with North American ballasts." I wonder if any North American collectors have been told that advice while trying to collect HID lamps from outside of North America.

This is false, except running European HPS lamps and regular saturated HPS lamps retrofit for mercury ballasts on American CWA ballasts.

It is true that there are Mexican CWA ballasts specifically designed for the Philips SON-T PIA high pressure sodium lamps and the Osram NAV-T Super 4Y high pressure sodium lamps too like I said in previous threads. In addition, Silverliner has had no problems running European 250w high pressure sodium lamps on North American 250w S50 CWA high pressure sodium ballasts since North American high pressure sodium CWA ballasts are designed to handle rising voltage over life since standard North American saturated vapor and standard European saturated vapor high pressure sodium lamps share the exact same arc tube chemistry. The only incompatibility issues I see are with running the saturated vapor high pressure sodium lamps on CWA mercury vapor ballasts.

Here is the post about Silverliner running a European 250w high pressure sodium lamp on a North American CWA ballast:

https://www.lighting-gallery.net/gallery/displayimage.php?album=3531&pos=40&pid=157797

Here is what he says about operating European high pressure sodium lamps on North American 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."

What CWA ballasts for HPS lamps different than CWA ballasts for MV lamps, that the former don't sensitive to the voltage rise of HPS lamps.

This is all a fuss about nothing if you ask me. Find out what ballast your lamp needs, and use it. Simple as that.

Anyone wants to do otherwise, it's up to them, but don't be surprised if things don't work as you expect them to.