Re: It may be better; or even worse.
Has that changed?
No, but you are missing the point.
At any time, someone could walk into steamnut's office and ask "that flurblewidget you made for Bloggs & Co 5 years ago ? Let's have a look at your records for CE marking it - we've had a complaint". They can then start picking apart his justification for having put a CE mark on it. So steamnut needs to be able to show, to whatever degree of evidence is needed, that he did in fact design it right and it does in fact qualify for having a CE mark.
Just a simple thing like "does it emit more electromagnetic interference than is allowed ?" isn't simple to answer unless you have actually paid more than the selling price of the flurblewidget to have it professionally tested. Using the technical file, you can say that it shouldn't have too-high emissions, but without actual testing then you can't be sure. The sort of kit to do the testing yourself isn't cheap, so unless you are doing a lot of it then that won't necessarily help.
While steamnut may have chosen good quality parts (all CE marked themselves where appropriate) and purchased them from a reputable source, and assembled them with care into a carefully designed system housed in a nice screened box - there's still no guarantee that it won't knock out next door's telly. Personally, I've knocked up an audio amplifier (well, stuffed a transformed, rectifier, and some amplifier modules in a box) which proceeded to do a good impression of a (roughly) 5MHz signal generator. A colleague tell of how in the past they had to certify all their products to new standards and setup a facility in a salt mine (in theory, a nice radio-quiet environment) - where they found that everything picked up Radio 2 due to a piece of wire left behind in a shaft that was resonant at just the right frequency to re-broadcast the signal down the mine.
TL;DR version. Yes you can use a technical file, but in the absence of actual authoritative test results, you can always be open to "not good enough, here's a fine for selling non-compliant equipment with a CE mark".
Biting the hand that feeds IT
