Creepage distance

Specifies the required clearance distance to maintain insulation between conductors. While the clearance is the straight-line distance between conductors, creepage distance is the distance measured along the surface of a material such as a substrate on which the conductors are mounted, and it varies depending on the material. The higher the insulating property of the material, the shorter the required creepage distance. Many safety standards for electrical equipment specify the creepage distance necessary to maintain adequate insulation.