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I'm a hobbyist that's currently developing a simple clock and hoping to make it into a small scale sellable product. It's a simple 5V USB clock with a ATTiny84 8MHz clock, a RTC-module and some WS2813 LED's. It's simply powered by a USB-cable and no power regulation is done on the chip.

Current regulations in Europe require it to be CE certified since it has MCU with a clock-speed of >9kHz. So if it didn't have the ATTiny84, it would not even be required for certification.

But now since I need to certify it, I want to do some testing to make sure everything is alright. However I want to do it in the easiest and cheapest way possible.

  • What would minimum testing be?
  • It it enough to do it with some standard in-house testing equipment
    (spectrum analyser, H-probe, LISN etc)?
  • Pre-compliance testing?
  • Or do I not have any other choice than to pay for a full compliance
    testing?
Lundin
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granstubbe
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    To get the certifications necessary for a commercial product, you will have to get testing at a certified test facility no matter what you do in-house. In-house testing can increase the odds of passing certs on the first try, but cannot replace them (unless you have a fully-certified in-house test facility, and it sounds like you don't). – AnalogKid Dec 17 '19 at 15:13
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    @AnalogKid The **have** to is incorrect. CE allows self certification for *certain* products, among which I think this clock is too. – Huisman Dec 17 '19 at 15:22
  • @Huisman yes you are correct, it is within self-certification so certification is not required, but if the product should be able to pass it if needed. – granstubbe Dec 17 '19 at 15:37
  • I guess "*it is within self-certification so certification is not required*" is a typo? If not, the statement is incorrect and a contradiction. **self-certification = certification**, Self-certification doesn't *demand* a certified test facilty, but to prove compliance to the applicable **directives** using such facility is wise. – Huisman Dec 17 '19 at 21:24
  • I think next to the EMC **directive** it should also comply to the RoHS **directive**. So, below or above 9kHz clock doesn't matter to that. – Huisman Dec 17 '19 at 21:37
  • @Huisman, yes you are completely right, it should be the way you write it. I agree that full testing ideally should be done. But if my estimations are correct, I'm so far from the limits that performing a certified test would not be necessary. Yes RoHS I'm also fully aware of and made sure to select components + PCB which satisfy it. – granstubbe Dec 18 '19 at 08:05

2 Answers2

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If your product needs formal compliance testing, you unfortunately need to have an accredited lab do the testing. [Edit] It's surprising to me that this product cannot be self-certified, but it sounds like you've determined it is necessary

At my workplace, we'll do pre-compliance verification using either a GTEM cell or a spectrum analyzer and near-field probe, essentially to validate that the product is ready for formal testing. In your scenario, I'd say near-field probe and spectrum analyzer is the way to go.

As expensive as compliance testing is, anything you can do to make sure you only have to do it once is important.

Drewster
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    This is incorrect. CE allows self certification for certain products. This self certification still demands formal testing, reporting, documentation. But it does not necessarily have to be done by an accredited lab. – Huisman Dec 17 '19 at 15:25
  • That's why I stated "IF YOUR PRODUCT NEEDS FORMAL COMPLIANCE TESTING" You can obviously sign a declaration of conformity and lie, but if you're going by the book... – Drewster Dec 17 '19 at 15:34
  • @Drewster This product will be in a category where no formal compliance testing is needed. And since it is so close to the minimum requirements for a device that even needs to be CE-certified. My hope was to gain enough confidence to sign a declaration of conformity without needing to take it through all expensive testing. – granstubbe Dec 17 '19 at 15:39
  • @granstubbe Ahh I see. In your case, the product doesn't have any switching supplies, isn't safety critical, doesn't connect to mains power, doesn't apply to the low voltage directive, and uses an off the shelf micro.. I would say there's plenty of confidence. Running a near-field probe can usually tell you if something is horribly amiss. In my industry everything needs formal testing, so I read "I need to certify it" and applied that train of thought :) – Drewster Dec 17 '19 at 16:09
  • Thanks @Drewster, that sounds promising! I'm currently looking into hooking it up to a spectrum analyzer and try to find both conductive and radiative emissions, even though it should be fine. I have TVS diode too for ESD protection that I feel pretty confident about. – granstubbe Dec 17 '19 at 20:11
  • What's makes compliance testing *formal*? And hos does formal compliance testing relate to self-certification? – Huisman Dec 17 '19 at 20:56
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    @Huisman Depending on your industry and the certification body, formal testing usually means going to an accredited lab, getting stuff set up, and then they'll run the test, generate an official report, and charge you a *lot* of money. Pre-compliance generally means running a test in-house or with a 3rd party lab that either isn't going to do a full test or isn't actually accredited to do the test for that certification body. Self-certification (I think) is you saying that - under penalty of law in the given country - you've done all necessary processes and testing for that certification body – Drewster Dec 17 '19 at 22:10
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Current regulations in Europe require it to be CE certified since it has MCU with a clock-speed of >9kHz. So if it didn't have the ATTiny84, it would not even be required for certification.

This is nonsense. Anything containing electronics needs to be CE marked. What directives that apply is another story.

The <9 kHz restriction was for radio electronics that sorted under the now withdrawn R&TTE directive and referred to 9kHz radio wave frequency. Intentionally emitted - not MCU clock speeds etc. This scope of 9kHz - 3000GHz has, as far as I know, been withdrawn in the current RED directive. Currently it just says "anything below 3000GHz".

The first thing you need to figure out is what EU directives that apply to the product. If it contains anything radio/wireless, then it must conform to the RED directive, which also covers EMC. And if you need RED conformance, then implicitly you also need to low-voltage directive conformance (LVD). LVD in such a context is mostly about product safety, "not allowed to catch fire" etc. If it doesn't contain radio, then it must conform to the EMC directive instead. There's also the environment directives RoHS + WEEE. For products containing batteries, WEEE in particular is a bureaucratic nightmare.

From there, you have to figure out which normative standards under each directive that applies. This isn't easy, one typically has to consult an EMC/CE marking expert such as a test house.

Once you know all directives and standards, you can make a draft EC declaration of conformity listing them. If you have that, then there is a self-certification procedure which doesn't require testing at a 3rd party test house/notified body.

This self-certification procedure is outlined in the respective directive. You have to assemble a "technical file" of the product, which is basically just about producing a pile of more or less relevant documentation. For RoHS you must be able to point out the component manufacturer's documentation (datasheets etc) where they claim RoHS compliance, for every single component in the product.

The problem with self-certification is that if your product turns out to be non-compliant, you have vouched for it in your EC DoC and you'll be legally responsible. One good thing with hiring a test house for formal testing is that you can prove that you've done everything you can to ensure compliance, should you end up in court.

Basically, the EU bureaucracy system is rigged to make it hard for small start-ups to make it to market without taking short-cuts, as described here.

As for what testing you can do in-house, it is almost impossible to measure radiated emissions outside a lab, and it is definitely impossible to perform radiated susceptibility tests.

If you don't want a formal test rapport where the test house is stating product compliance, you can test these somewhat "cheap" (around 1k-2k€) through pre-compliance testing at a test house.

Lundin
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  • The device only falls under EMC and RoHS and is a low power device (0.5 - 1W) so even if there were emissions, the likelihood it would be above limits seem quite low. I believe my budget reaches its absolute maximum at a pre-compliance test where I've been quoted ~1.5k€ for testing all areas. Hopefully that would in absolute worst case scenario hold up in court. But the system really is rigged against start-ups.... – granstubbe Dec 20 '19 at 19:52
  • And by now I've definitely spent more time on deciphering bureaucracy than actually developing the product... – granstubbe Dec 20 '19 at 19:59