Electronics > Projects, Designs, and Technical Stuff

Self-Certification of consumer electronics

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ricko_uk:
Hi,
if you want to make and sell simple low voltage low power electronics (like a small PCB with display, keypad etc) for consumer use (not just hobbyist).

The PSU I buy in already with all certifications. What about the PCB/enclosure assembly?

1) what are the minimum requirements and certifications you need to issue/get? Which ones for UK/Europe and which ones for US?
2) If any can you self certify them?
3) I think you can self certify the CE mark, what do you need to do to be able to self certify it and be able to stick the CE mark on it?

Many thanks :)

AndyC_772:
You need to have evidence that your product is compliant, so that if challenged by the authorities (Trading Standards in the UK), you can show that you were justified in applying the CE mark. You can self-certify, but that doesn't mean just sticking the mark on the back of the box and calling it a day.

As far as safety is concerned, if you're using a mains PSU that's already approved, you may be able to claim compliance by inspection.

EMC is much harder, though. Without testing the complete product, I've yet to hear any possible valid argument that doesn't involve at least some testing at an EMC lab. Most commercially available power supplies are pretty marginal in terms of emissions even on their own, never mind when connected to something that's not just a pure resistive load.

Pragmatically, the chances of your product ever being picked up and questioned by the authorities are very small indeed, unless someone gets hurt, but that's not really a good reason to join the list of cowboys who just ignore the rules.

Gyro:
If you're buying in a power supply (you don't indicate open frame or wall wart so I'll assume wall wart), then you will at least want copies of their certifications for your Technical Construction File, and have sufficient confidence in their validity, ie. that they haven't self certified. They should have used a reputable test house, particularly for LVD (safety) testing. You can't just switch PSUs on the fly either, as that would affect your overall certification. If it is any sort of open frame PSU then you become responsible for LVD too, its safe enclosing, components, wiring etc.

With LVD taken care of, then yes, you have EMC to worry about. You need to purchase the relevant standard for the equipment that you are building (there are no 'freeware' copies) and verify compliance. On some equipment, you can do the sums and prove that you can't possibly emit sufficient RF energy to exceed the limits, but that certainly won't be the case for a mains block powered device.

You really need to do radiated and conducted emissions, using your chosen mains block. You may also need to do susceptibility and ESD too, depending on what the function the device is and the consequences of it failing. (ESD, you can probably do yourself to a reasonable level of confidence - you probably want to do this anyway if you want to be confident about not getting lots of customer returns).

You didn't say if you possess any EMC pre-compliance test equipment, but without it, I can't see that you would have the evidence needed to attempt self-certification.

P.S. Just to try to add a few specific answers to your questions:

1) There are laid out in the specific standards, based on product type. At the moment, UK and EU standards are still harmonized (according to the BS-EN numbers on the BSI site anyway). US is based on FCC standards. For example, you can find the UK EMC standards at https://shop.bsigroup.com/Browse-by-Sector/Manufacturing/Electromagnetic-compatibility/Electromagnetic_compatibility_standards/.

2) Yes you can self certify, given sufficient evidence that you comply with the relevant standards.

3) The method of self-certifying is by creating and maintaining a Technical Construction File (TCF), which documents the evidence that supports your claim to comply with the relevant standards. This must be available for examination in case of a challenge.

Basically, the test / compliance requirements for your (quite specific) product type comprise EMC (Emmissions - Radiated and Conducted, Susceptibility - Radiated and Conducted, and ESD) and LVD (Low Voltage Directive - Safety). Talking to a friendly local test house can save you an awful lot of time - Consultants (of any description) tend to be expensive!

ricko_uk:
Thank you Chris and AndyC_772 for your very detailed replies, much appreciated!! :)

splin:
This thread about adafruit's certification (or lack of)  is interesting although mostly about their radio products. It seems that Sparkfun don't certify (most)  of their products either but they both seem to get away with selling a lot of stuff:

https://forums.adafruit.com/viewtopic.php?f=8&t=113747

I believe that there is a *lot* of stuff sold which hasn't been expensively tested by an RF test company, by small companies - but obviously not many want to talk about it. How can $25 products, such as test gear sold to hobbyists, which might only sell in the few hundreds at most, cover $10K+ EMI testing cost and still make a profit?

There must be quite a few posters here who sell there own designs.  It would be interesting to have an anonymous poll to see how many do and how many would admit to selling non certified product or product which hasn't been third party emissions tested. After all the chances that a small voltage reference module for calibrating DMMs or an Arduino temperature sensor shield would cause real world problems must be vanishingly small although theoretically possible if marginally stable and oscillate in some conditions. Is Dave's uCurrent CE certified for example?

I wonder if anyone ever gets prosecuted or at least told to stop selling product unless dangerous or it grossly violates emissions regulations and causes real problems? I'm talking about small companies selling their own designs here - not re-sellers of cheap, poor quality Chinese tat or larger companies selling large volumes of consumer product.

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