Is there a design practice for having both a varistor and a class X or Y capacitor for safety and voltage transient protection on AC circuits?
At my work, a previous employee designed a simple AC to DC converter using an IRM-15-12. The design just includes a varistor at the input, and nothing else. Unfortunately, design documentation is lacking (there's no documentation for this PCB.)
There does not seem like there's anything wrong with the design. I am just curious if there should be a class X or a Y capacitor in addition to the MOV.