Elektor has produced a new video series (not tied to KiCad):
- PCB Clearance and Creepage Distances, Part 1: Which Standard Applies?
- PCB Clearance and Creepage Distances, Part 2: Which Criteria Apply?
- PCB Clearance and Creepage Distances, Part 3: Putting it All Together
(evs.ee and lvs.lv often offer identical national standards in English)