UL/CE certified AC/DC power supply

[hebnern]

I am working on a project that requires a PCB mount 5V 3-5W AC/DC converter. I want to get the product UL/CE certified, and was told that the cheapest and fastest route would be to find a pre-certified supply. I have found a number of options, and based on a few parameters have landed on this one:

http://www.micropowerdirect.com/Pages/Product/ACDC/MPL/Prod%20ACDC%20MPL03.html

The one weakness that I can see is it is only EN55022 class A.

Is a class B supply _required_ for a consumer product?
If I wanted to make this converter class B, what filtering would be required? Just a Pi filter on the input?
What would the agency approval cost implications be if I added the filtering myself versus buying a certified filter like ACFM-01 that they mention in the datasheet?
Are there any other good options out there for PCB mount AC/DC converters?

[hebnern]

From what I have read, it is possible to go with a Class A supply for consumer equipment, but you have to add a warning stating that it might not work properly and its up to the user to take the necessary precautions.  That's lame, so I'll just suck it up, and get a nice class B supply like the NFM-05-5.

[AndyC_772]

If you want your product CE marked then you'll need to get it tested either way. The emissions from your product will depend on the other components in your design, the layout and the enclosure too, and it's certainly not the case that you can buy a CE marked power supply and then claim emissions compliance on that basis.

A CE marked power supply will save you some time and effort when it comes to getting safety approval, though - but that has nothing to do with the class A / B certification.

In my experience, many power supply manufacturers have trouble understanding that in order to be usable, they have to not only pass (particularly conducted) emissions on their own at full load; they have to pass with good margins under all operating conditions. Without margin to spare, once their PSU is connected to a real circuit which inevitably generates some noise of its own, the complete system cannot pass an emissions test. Whilst their product may technically be legal and compliant, it's not commercially usable.

[hebnern]

Yeah, I understand that I will have to have it tested either way, and that there will be other factors than just the power supply. But selecting a supply that has some certification at least is a good start toward compliance. I understand that it does not guarantee compliance of the entire device though.