For one-off, bespoke electronic products, or ventures on low budgets, what is the cheapest way of ensuring the product conforms to EMI/EMC requirements of CE marking? This can be at design time and / or throughout the manufacturing process.


  • A small-run, electronic microprocessor based controller (using a CE-Marked zero-cross solid state relay) intended to switch on or off a 2 kW load such as a consumer grade 240 V, 2 kW blower heater.

  • A one-off CNC machine that utilizes CE-marked, low voltage motors and servos, and is controlled by a microcontroller and miscellaneous circuitry

  • A new venture into producing LED lighting with controllers - typically switching 10 W loads; using PWM to control brightness; controlled by a micro-controller; using SMD LEDs, and a CE-marked switched-mode 24 V, 3 A PSU.

Obviously there must be logical principles which one can apply to allow one to bypass other expensive conforming methods. For example, connecting two CE-marked appliances to each other where they are intended to do so would most likely not need any further testing.

The problem is that for more complicated scenarios getting products approved by external companies that provide CE-marking assessments can be incredibly expensive. Also, I have not found any particularly affordable equipment/methods to carry out EMI/EMC testing - and not being an expert in EMI/EMC means I would not be confident about using such equipment effectively.


1 Answer 1


First of all, the main documents you need to know:

Those documents form the basis of your work. Also, they define if your device is subject to the directive or not. Depending on the case, you could also be subject to the R&TTE Directive and RoHs Directive).

The Annex I of both documents informs us on the essentials requirements to meet. Mainly, it says that your product must be safe for humans, pets and property and that it should not be impacted by the electromagnetic emissions of other nearby devices nor it should impact them with its own emissions.

What's really interesting lies in the Annex II of the first document and in Annex IV of the second document. These parts defines the conformity assessment procedure you'll have to follow.

There are 8 procedures (called modules) of conformity assessment:

  • internal production control (module A);
  • CE type-examination (module B);
  • conformity to type (module C);
  • production quality assurance (module D);
  • product quality assurance (module E);
  • product verification (module F);
  • unit verification (module G);
  • full quality assurance (module H).

In our case, the one to follow is called Internal Production Control. Basically, what you have to do is write the technical documentation. This document should be made of those parts:

  • a general description of the electrical equipment,
  • conceptual design and manufacturing drawings and schemes of components, sub-assemblies, circuits, etc.,
  • descriptions and explanations necessary for the understanding of said drawings and schemes and the operation of the electrical equipment,
  • a list of the standards applied in full or in part, and descriptions of the solutions adopted to satisfy the safety aspects of this Directive where standards have not been applied,
  • results of design calculations made, examinations carried out, etc.,
  • test reports.

We learn what we have to do in order to respect the directives. The main constraint here will be showing that you have indeed accessed the harmonised standards. This can cost quite a hefty sum of money. However Afnor (the French certification organism) provides subscription to their database, which can be cost effective compared to buying individual standards). Your local certification organism should have a similar offer.

The harmonised standards list to be followed is available here:

This document will then have to be kept for up to ten years after the last product manufactured was sold.

Doing this will allow you to affix the CE marking and provide a certificate of conformity to your customer.

Even if this is a lighter method for CE certification, it still involves a bit of work. However, this is something that should be done anyway (if just to make sure your product will perform well and as expected in all conditions).

EDIT : There is a European Union website that shows all the currents harmonized standards and all the different Directives your product may be subject to: http://www.newapproach.org/Directives/

TL;DR: At least two directives applies, one related to EMC, the other to Low Voltage Devices. The procedure to follow is called Internal Production Control. To comply, one has to draw up a technical documentation whose main part is the harmonised standard list followed is added.

  • $\begingroup$ Thanks - excellent answer. I would mark as accepted answer, except I would be particularly interested to hear how others on low budgets have managed to confirm conformity. $\endgroup$
    – Jodes
    Jan 21, 2015 at 11:04
  • $\begingroup$ No worries! I'm no expert anyway, I just had to do the research for work, so it feels safer to wait for another answer! $\endgroup$
    – gromain
    Jan 21, 2015 at 11:11
  • $\begingroup$ Hi @Jodes, was this answer finally satisfying, or did you find more details somewhere else? $\endgroup$
    – gromain
    Oct 8, 2015 at 16:21
  • $\begingroup$ It was helpful, yes, thanks - sorry I forgot to mark the answer as accepted. In the end I also purchased a book "From Prototype to Product" by S.T. Segaran which helped quell some fears - although I never did get a product to market because without a large budget I was not confident that my experience was enough to ensure conformance with the regulations. It's a shame because at the same time I'm convinced the product would have been acceptable. $\endgroup$
    – Jodes
    Oct 9, 2015 at 12:13

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