Since PCBs are built on organic substrates with some salt and moisture content, high electric fields between conductors can lead to the growth of CAF via an electrochemically induced reaction. This can happen at much lower voltages than would be required to cause dielectric breakdown. Fault arcs on busbar sets and switchboards Title Author Subject Fault arcs on busbar sets and switchboards-The probability of appearance of a fault arc on a set of busbars cannot be considered as non-existant. How to reduce arcing probability, limiting consequences. -. Insulation standards for isolated components (such as an isolated gate driver) do not address CPG and CLR. IEC 61439 treats clearance and creepage as verification issues because they sit at the center of insulation. These result from a gradual decrease in the inter-phase or inter-phase to ground insulation resistance.
[PDF Version]