I am working on a PCB with different AC voltage levels and some low voltage circuitry. I also have some low voltage circuitry with a ground relative to these high AC voltages with some opto couplers to connect the 2. The problem I am having is that I now have different nets with small voltage differences between them that don’t need big clearances. But they do need big clearances to the other nets. There are even nets in this layout that cross multiple filled zones, some of which I need to keep proper clearance from but others I don’t, and in the mean time there are also electronics in those same zones that need small clearances.
One good example of a problem I am having on my board: lets say I have a ground plane on which I have a microcontroller which is connected to the right side of an optocoupler. The left side of that optocoupler is on that same ground plane, but that side of the optocoupler is a few hundred volt higher than the other side. Therefore I need proper clearance from that side to the ground plane. This clearance should be bigger than the distance between those 2 pins on the left side of the optocoupler which is electrically ok because the difference between the pins on the left side of that optocoupler is relatively small. Is there any way that within the features of kicad, I can have different clearances between certain nets but not others.