redwire - thabk you for the reply
in IPC-2221 paragraph 6.3 you can find requirment for Z Axis i Quote
"6.3 Electrical Clearance : Spacing between conductors on individual layers should be maximized whenever possible. The minimum spacing between conductors....... layer to layer conductive spaces (z=axis), and between conductive materials ... and conductors shall be in accordance with table 6-1,....."
redwire :can you kindly share some examples of UL60950 clearance requirments fro PCB layout for Z axis ?
I understand that Allegro does not support Z axis clearance constraints .
About the 2 mil clearance being enough for 50V - this was only an example
BUT sometimes i have up to 1500 v and higher