I'm currently designing a power supply with high isolation between primary and secondary sides and have to comply to standard distances on clearance and creepage.
My question is regarding creepage, I understand how it works on the same surface, and that the distance can be increased by adding slots or barriers. But I have been looking (without success) for information about what happens between layers, as in, if I have components on the top and on the bottom that need a certain creepage distance.
Do I need to consider the distance towards the board outline, up/down to the other layer and to the component, like path 2? Or only path 1 should be considered? Same thing with internal layers.
Hope I explained correctly but if not feel free to ask questions. I'd appreciate any references on the issue or experiences regarding this.