What is Creepage
Creepage is the shortest distance along the surface of an insulating material between two conductive elements. It ensures the safe operation of voltage circuits and prevents electrical arcing or short circuits between conductors that are separated by an insulating material.
Unlike clearance, which measures the shortest distance in the air between two conductive elements, creepage takes into account the surface of the PCB. It is often seen on the board surface between traces, as opposed to clearance, which is more likely to occur between component surfaces of high voltage circuitry.
The spacing between traces on the PCB surface is particularly important in relation to creepage. Trace spacing can impact the creepage distance, with closer spacing increasing the risk of electrical breakdown. It is worth noting that following the surface contours can greatly increase the creepage distance relative to the clearance for the same charged surfaces.