In a message dated 04/10/2004 03:15:13 GMT Standard Time, [email protected] writes:
I have two questions for the list today. First, product is ITE tested to EN 60950. Primary power (115 VAC) is fed to a printed circuit board. I know there are creepage and clearance requirements for the etches carrying AC that run on the surface of the board, or on any layer for that matter. That is there are spacings required between AC etches and other etches whether signal or ground or whatever. What I cannot recall is if creepage and clearance applies to etches on different layers. Say AC on etch on surface and signal on etch on first inner layer. Assume standard multilayer board with typical thicknesses. Don't recall 60950 saying anything about that and don't have a copy of the standard to review. Does creepage and clearance apply to this situation? Does the high insulation value of the FR-4 play any part in reducing the requirements? Scott, EN 60950 and EN 60950-1 do have requirements for the separation of a primary trace on one layer and traces in other circuits on another layer. What you are dealing with, however, are distance through insulation requirements and not creepages (which are along a surface) or clearances (which are through air). I would not recommend trying to design a product to comply with EN 60950 (inc. -1) unless you have a copy of the standard, since there are many options to consider. Regards, Richard Hughes
