I saw this image where the "white trace" is (I think) trying to separate high current 220VAC.
Do you know what is that white paint made of?
Image source: Shelly Facebook Page
While trying to find an answer to this, I looked (without much success) at several sites talking about PCB protection, isolation, and high voltage PCB design. Most of them focus in cutting your PCB, get wider clearance and traces, paint the entire PCB with silicon, etc. I could not find any reference to a colored paint/coating that is used in between traces like the image:
- CALCULATING SPACING BETWEEN PCB TRACES FOR VARIOUS VOLTAGE LEVELS
- PCB INSULATION MATERIALS
- MetaLine isulation coatings
- Electrical isulation materials
- Silicone Conformal Coating
- Essential guide to Conformal Coating
- How to protect your PCB?
- Altium: High Voltage PCB Design for Arc Prevention
- High Voltage PCB Design for Arc Prevention (video)