The creepage distance requirements for secondary circuits according to clause 8.9.1.12

EMengineer

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Hi everyone. I got a little confused while reading clause 8.9.1.12 of IEC 60601-1 3.1 edition regarding creepage distance (c.d) and air clearance (a.c) for secondary circuits. In this edition, I found that if the secondary circuit doesn't have protective earthing, the c.d and a.c values of the mains part should be used for the secondary circuit. In the new A2 amendment, an additional requirement states that this overvoltage requirement is not applicable if the MEANS OF PROTECTION required by 15.4.3.5 and 15.5.1.1 are fulfilled. Does this mean that a standard IEC 601-compliant class II PSU (which I believe complies with 15.5.1.1) would provide a separate secondary circuit for which the overvoltage requirements should not be applied?

I wonder, prior to this A2 amendment, was it always necessary to use c.d and a.c values for the mains when designing the separation between the secondary circuit and the floating applied part in the case of a class II PSU?
 
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