I have seen on various mains powersupply PCBs that they have a lot of silkscreen lines near the high voltage areas. So my question is that does the silkscreen helps rise the voltage rating of that section or is it just to mark that area as the high voltage one.
In terms of voltage creepage rating is there a difference between Left and Right?
This is an image from smps.us and this table shows the creepage distance for 100Vdc for 1. External, 2. Internal, 3. Coated.
Does the coated here means only coated with soldermask? Or does adding silkscreen to the mix also helps somewhat?