When a manufacturer is thinking of the European Union (EU) as the next market for its electronic equipment, EMC compliance is one of the must-haves on the list of approvals. Unless a company has dedicated quality personnel to ensure testing and certification is done to the letter, the approval process can be quite complicated for engineers – from identifying the correct standards and models for testing to writing the declaration of conformity and preparing the product for testing. This article will explain what engineers need to do to demonstrate compliance.
What the EMC Directive Is and … Is Not
Most electronic equipment that will be sold in the EU needs to comply with the EMC Directive 2004/108/EC. While the directive sets rather tough requirements to regulate the product’s electromagnetic disturbances, it is not a safety directive because it only covers equipment’s EMC concept. Compliance with the EMC Directive alone does not enable CE marking, a mandatory conformity mark for products placed on the market in the European Economic Area; the product must comply with all applicable directives to earn the mark.
There Is a Standard for You…
Out of hundreds of standards featured in the EMC Directive, the manufacturer must pick the right standard for the product and bears responsibility for the choice. This is often a point of confusion for the US engineers, who, if they work with a third-party testing and certification body, believe that the registrar should be responsible for testing to the correct standard. While most testing laboratories will help identify standards applicable to a particular piece of equipment, the responsibility remains with the manufacturer. It is a good idea to get acquainted with the standards to be able to choose the right one.
Too Many Choices?
Each standard in Directive 2004/108/EC governs a particular type of equipment, such as laboratory, IT, industrial or household. The standards determine the strength and the limits for every test used to evaluate the product; this means that if equipment is used in ITE applications, it will be tested to requirements different from those used for industrial equipment. Included below is the hierarchy of the standards and where to find them.
Top level generic and product family standards describe the overall EMC requirements for the product. Engineers should use generic standards only when there is no family standard covering the product.
Many organizations sell the standards, including ANSI and Global Standards. For CE marking, these standards are listed on the EU website as the harmonized standards list or are featured in The Official Journal of the European Union (OJ), the only periodical published every working day in all official languages of the EU.
Basic standards are one step down the hierarchy. They explain the individual procedures used to test products for EMC compliance. The basic standards are listed in the Normative References section of the product family and generic standards. They are not listed in OJ.
Testing the product to the latest version of harmonized standards is the main method of compliance with the EMC Directive. However, if a product had been tested to the version of the standard that since then expired, manufacturers can perform a gap analysis to identify only new requirements to which the product needs to be re-tested. If requirements of the new version do not affect the product, the manufacturer can prepare documentation proof with justifications, explaining why re-testing is not necessary.
If an electronic product is intended for export to the EU, EMC compliance is one of the must-haves on the list of approvals. (photo courtesy of TÜV Rheinland)
The conformity assessment procedure sets out steps to follow to demonstrate the product’s EMC compliance. Engineers should begin by reviewing harmonized standards to determine the one applicable to the product. They need to decide how to actually test the product – themselves or with the help of a third-party laboratory. Because of the procedure’s complexity, most companies choose the latter and must find the right partner to work with. When looking for laboratories, engineers need to ensure that prospective registrars devote the time to educate them on what EMC testing involves, how long it takes and what is required because open communication is crucial to the success of the endeavor.
Some engineers may not be aware that they must review all the models, or versions, of the product to determine which ones need to be tested. The directive requires all possible product configurations be included in the EMC assessment. If there are five models, and each differs from the others in terms of design and has different electrical components, all five need to be tested. If the difference is not design-related, such as a color scheme or shape, this model can be excluded from the list.
To select models for testing, many companies take the so-called “worst case” representative(s) approach. They select one or more of the most advanced versions of the product and apply the results of their tests to models simpler in design. Engineers should keep in mind that “the worst case” model for immunity testing may be different from the “the worst case” candidate for emissions testing. The company may need to test more than one variation or use different configurations for emissions and immunity testing. As with the standard selection, the manufacturer is responsible for identifying the “worst case(s)” and possible configurations for testing, but a laboratory can assist with making the decision.
Determining in advance what models need testing will help a testing provider give an accurate quote from the start. If a laboratory discovers that other models need testing after the initial quote was issued, it will need to issue another quote and schedule time to test additional models, adding time to the process.
Once the company determined which product versions to test, it needs to prepare technical documentation in accordance with Annex IV. The documentation file should contain necessary information to easily identify the product, such as general description, environments where it can be used, warnings and manuals.
After the testing is done, test reports will go into the file to provide evidence of compliance with harmonized standards. If the company did not have every variation of the product tested, the file should explain why certain models were excluded and how it selected the “worst case” representative.
Manufacturers must always keep their technical files up-to-date. If a design change is made to the product, the equipment might need to be re-tested – fully or partially – and the technical file needs to be updated accordingly.
Annex IV of the directive instructs manufacturers to prepare the EMC declaration of conformity (DoC) for the EU as part of technical documentation. According to Part 2 of the Annex, DoC must include the following:
- Dated reference to the Directive 2004/108/EC
- Identification of the product
- Name and address of the manufacturer
- Name and address of the authorized representative in the country of distribution
- Dated reference to the specifications (A manufacturer must include the date of the standard to which the product was tested. As new versions of standards are issued, old versions become invalid and the product may need to be tested again to the new specifications.)
- Date of declaration of conformity
- Identity and signature of the responsible party
Engineers do not need to list the basic standards in the DoC, only harmonized product family or generic standards. They should remember that for a product to be CE marked, it must comply with all the applicable directives and related harmonized standards and these directives and standards must be listed in the DoC.
The directive does not specify a format for the DoC and documentation file as long as they include the minimum required information. If any of the minimum required content is missing, the DoC is considered incomplete and invalid, which might lead to an appropriate action from the competent authorities of a member state. The following standards are a good reference on how to prepare a DoC: EN ISO/IEC 17050-1:2005 and EN ISO/IEC 17050-2:2005. CENELEC has also published a specific guide for the DoC: “CENELEC Guide 16 on the implementation of New Approach directives and the Low Voltage directive with respect to the EC declaration of conformity.” A testing laboratory may also provide engineers with a DoC template to streamline the process.
The directive requires manufacturers or their authorized representatives to hold the technical documentation in the country of distribution for at least 10 years after the last manufacturing date. If the company does not have a local representative, whoever places the product on the market is responsible for providing the technical documentation and DoC to competent authorities upon request within a reasonable timeframe.
Of course, manufacturing products according to the technical documentation is paramount. This way, the products are consistent in quality and performance per EMC phenomena.
Working with a Notified Body
Occasionally, manufacturers might want to go the extra mile to ensure that products are tested to the correct standards and are in full compliance. In this case, the company has an option to send the technical file and EMC report to a Notified Body (NB) for review. Specifically, a NB does the following:
- Reviews the technical file to ensure the essential requirements of the Directive are met;
- Reviews the technical file to ensure that it clearly demonstrates that all the Directive requirements are met;
- If everything is in order and complete, issues a statement of opinion to be included in the technical file.
Harmonized standards are occasionally updated, with the revisions listed in OJ well before they become mandatory. When an existing version of a standard expires, manufacturers must use the new standard on the DoC as the old one no longer shows compliance with the directive. Often, this means re-testing the product to the new standard.
Revisions to basic standards are more challenging to keep up with; there is no publication comparable to OJ for the basic standards. If engineers use a product family or generic standard that has undated basic standard references, they must take into account changes or updates to basic standards.
Don’t Tempt Fate
If a manufacturer tries to place a non-compliant product on the EU market, it could face penalties. Penalties differ by the country and range from removing the product from the market and prohibition or restriction of the free movement of the product to liability for a fine and/or imprisonment. Typically, a relevant enforcement authority will give a manufacturer a chance to fix the problem and ensure the product is correctly CE-marked; the measures are much stricter when consumer safety is at risk.
Getting Ready for the Test
To make the testing process go smoothly, engineers are well advised to prepare for testing in advance. They will need to get ready all of the product information, including the product’s description, function and intended environments, product variations, as well as electrical specifications, including clock speeds of all microprocessors.
Engineers sometimes forget to factor into their schedules various lead times involved in a testing procedure. In addition to the lead time to issue a quote, the testing provider may not be able to test the product right away if other products are in the queue. After the tests are done, there is a lead time for the laboratory to issue a report. If a product fails part of the test, the manufacturer will need to make changes to it and have it re-tested in that area, which will add more time to the process. Engineers should ask their testing partners about lead times before committing to working together as lead times vary between laboratories.
When preparing to ship the product to the laboratory for testing, engineers need to include everything that is needed to operate the tested product, including step-by-step operating instructions so that test personnel know how to properly operate the equipment. When necessary, supporting equipment that is not subject to the test also needs to be shipped. For example, if a printer is tested, a manufacturer needs to include a computer, a USB cord, and power cords for the computer and printer.
In certain instances, a mobile EMC laboratory will come to the manufacturer’s site to test the equipment.(photo courtesy of TÜV Rheinland)
Hosting the EMC Test Crew
EMC evaluations typically take place in a specially equipped laboratory; however, there are three instances when a testing provider will travel to the manufacturer’s site to conduct tests. First, if a product is very large, such as a built-in-place industrial system, which cannot be fitted into the laboratory space. Second, if a product requires substantially more power than can be provided in the laboratory. Third, if a product requires special auxiliary equipment that cannot be shipped to the laboratory.
There are some differences between the EMC testing performed in the laboratory and at the manufacturer’s site. When done in a laboratory, radiated immunity testing takes place in an EMC chamber that is completely isolated from its surroundings and allows a full range of tests to be performed. When testing is done onsite, only limited frequencies are permitted. The deviations in testing are allowed when at least one of the three above-mentioned conditions are satisfied. The decision to test at the manufacturer’s site should be documented and justified in the technical file.
Before the testing crew arrives at the manufacturer’s site, the company personnel needs to prepare the tested product and supporting equipment, clear the space around the tested equipment and ensure that it runs in a continuous operating mode. If more than one product variation needs to be tested, all models should be ready for evaluation in advance, whenever possible. Reconfiguring equipment while the laboratory team is waiting on site will add time and cost to the testing process.
EMC testing done in the open area test site (OATS).(photo courtesy of TÜV Rheinland)
After the testing is completed, the laboratory will provide the customer with a report stating the test results. If the product falls short in some area, the report will identify the problem. The customer can adjust the design or troubleshoot the problem and then send the modified version back to the laboratory to re-test it in the area where it failed. While implementing changes to the product, engineers need to be aware that the modifications might affect the EMC phenomena in more ways than intended. Depending on a modification, they may consider testing the product in more areas than only where it previously failed. Once the product demonstrates full compliance, the laboratory issues a final report to be included in the technical documentation file.
In addition to the EMC testing, a product exported to the EU needs to comply with a great number of other regulations. To save time and money, engineers are advised to inquire if their test laboratories can assist with other necessary approvals. Consolidating all of the testing needs with one laboratory eliminates the inconvenience of managing multiple laboratories, streamlines logistics, simplifies documentation and results in a faster, more efficient and cost-effective compliance strategy.
serves as Senior Business Manager, EMC and Telecommunication Services, at TUV Rheinland of North America, Inc. He has more than 12 years of experience in regulatory compliance in testing and certification. Ozturk graduated from University of Missouri-Rolla with a degree in Electrical Engineering, with an emphasis in EMC. He can be reached at OOzturk@us.tuv.com.