Where can you find/purchase a corner grounded delta (B phase) Din rail mounted 240V

[JNjie]

I found a HJL36100 from Square D that comes with a din rail kit. This breaker is rated for B phase grounding

 

[kwired]

I found a HJL36100 from Square D that comes with a din rail kit. This breaker is rated for B phase grounding

The QOU3100 should be acceptable for grounded phase systems as well - 240 volts nominal though

Your HJL series breaker is a 600 volt breaker, 150 amp frame, with 100kAIC interrupt rating (@ 240VAC). Probably more pricey then a QOU if you don't need such a high interrupt rating.