Creepage and clearance are the two fundamental isolation distances on a printed‑circuit board. Creepage is the shortest path along the surface of the insulating material, while clearance is the shortest straight‑line distance through air. Both distances must be sized according to the working voltage, the pollution degree (environmental contamination), and the material group of the board.
The IEC 60664‑1 standard provides tables that translate voltage and environmental conditions into a creepage factor k. This factor is multiplied by the working voltage to obtain the minimum required creepage distance. Clearance is usually derived from a separate factor that accounts for air‑break strength and is often larger than creepage for the same voltage.
Designers use these calculations early in the layout stage to ensure that trace spacing, solder mask clearance, and component placement meet safety requirements without excessive board size. Adjusting the material group (e.g., TG, TG2, TG3) or improving the environmental rating can reduce the required distances and enable more compact designs.
V = working voltage (V)
What is the difference between creepage and clearance on a PCB?
How do I determine the pollution degree for my PCB environment?
What factors affect the creepage distance on a PCB?
How do I find the appropriate material group for my PCB?
Can you explain how to use the IEC 60664-1 standard for creepage clearance calculations?
What are some common materials used for PCBs with high insulation requirements?
How important is creepage distance in PCB design?
Results are for informational purposes only and do not constitute professional advice.