Update on the European Union's EMC Directive

By Dag Björklöf and Roland W. Gubisch

The EMC Directive, 89/336/EEC, came into force in 1992 and has been mandatory for CE marking of electronic/electrical products since January 1, 1996. Like other directives based on the "New Approach" principle, it lays out essential requirements without specifying technical parameters in detail. These are to be found in "harmonized standards," which may be used for presumption of conformity with the essential requirements of the directive with which they are harmonized. This approach allows the requirements to be easily adapted to new technical developments through revision of the standards themselves rather than revision of the legislation. Note, however, that standards are not legislative documents: their use is voluntary, and they may be only one of several means of showing compliance with a directive (cf. the Technical Construction File, or TCF, route as stated in the EMC Directive).

Product Directives Including EMC

93/42/EEC Medical devices.

90/385/EEC Active-implantable medical devices.

98/79/EC In vitro diagnostic medical devices.

90/384/EEC Nonautomatic weighing instruments.

96/98/EC Marine equipment.

Table I. CE marking directives of the New Approach type.

Product Directives Including EMC

95/54/EC EMC directive for motor vehicles and separate technical units (STU)/el. subassemblies (ESA).

<97/24/EC EMC directive for two- or three-wheel motor vehicles and separate technical units (STU).

95/56/EC Alarm systems and immobilizers.

Table II. CE marking directives.

Like the Low Voltage Directive (LVD) and the Machinery Directive, the EMC Directive is a "horizontal" directive in the sense that it covers a broad range of different products. Other, "product-oriented" directives may in some cases overrule these horizontal directives—as, for example, the Medical Devices Directive (MDD), 93/42/EEC, which contains provisions corresponding to all of the protection requirements in the three horizontal directives and thus supersedes them. Tables I and II show product directives including EMC (emissions and immunity).

New Approach directives published after 1990 make reference to Modules A through H, which are intended to comprise a "Global Approach" to certification and testing. These modules define conformity-assessment procedures relating to both the design and the production phases, and provide alternative procedures where reference needs to be made to EN 29001, 29002, or 29003 (ISO 9001, 9002, 9003) or to the role of a notified body in the assessment process. Since the EMC Directive was published before the Global Approach was implemented, it does not refer to these modules but instead prescribes specific EMC routes for compliance, in Article 10 (1–5). Article 10 (1) is nevertheless quite similar to Module A, which describes self-certification.

Application of the EMC Directive

At the time of its publication in the Official Journal of the European Communities (OJ) on May 12, 1989, the EMC Directive was not supported by any adopted EMC standards. Since 1992, however, a number of "harmonized" standards have been published to the EMC Directive (that is, they are harmonized with it).

In some cases, the original standards have been revised more than once. To qualify as a suitable standard for demonstrating conformance to the EMC Directive, the standard must be approved by either CENELEC (the European Committee for Electrotechnical Standardization) or ETSI (the European Telecommunications Standards Institute) and published in the Official Journal. CENELEC often makes use of existing IEC (International Electrotechnical Commission) and CISPR (International Special Committee on Radio Interference) standards.

Today there is a reasonably well-established resource of emissions and immunity standards to draw on. EMC standards are continuing to evolve rapidly as are interpretations of EMC policy. This presents quite a challenge for the conscientious manufacturer seeking to select the right test standards and procedures to ensure EMC compliance both now and in the near future. As of February 27, 1999, about 110 standards including a number of standard amendments had been published in the OJ as harmonized with the EMC Directive. This number should increase over the remainder of the year, as several new and revised European standards have been ratified by CENELEC (CLC) and are now awaiting publication.

The incentive for manufacturers to comply with EMC regulations continues to grow. Full accession negotiations have begun with Hungary, the Czech Republic, Estonia, Slovenia and Cyprus. Entry into the EU for most of these countries is expected early next century.

Accession talks for later entry into the EU will also begin for Bulgaria, Romania, Slovakia, Lithuania, and Latvia. Most of these countries have already begun harmonizing their national policies and standards with those of the EU. Negotiation mandates also exist with Switzerland.

EMC Requirements

The essential requirements of the EMC Directive address both emissions and immunity. This directive applies to all "apparatus liable to cause electromagnetic disturbances (emission) or the performance of which is liable to be affected by such disturbances (immunity)" (Art. 2). In addition, it covers not only components that have a direct function intended for the end-user and that are placed on the open market, but also complete systems. The latter might, however, in certain cases be regarded as compliant if they are built up out of individually CE-marked apparatus that fulfill all EMC requirements relevant for the given application (this is known as the modular approach).

Although they could be considered as falling within the scope of the directive, quartz wristwatches and incandescent lamps (bulbs) are exempted according to an agreement reached among the Member States' government experts on November 21, 1995. Totally excluded (for both emissions and immunity) from the EMC Directive (nonrestrictive list) are the following apparatus:

Radio equipment used by radio amateurs (unless the apparatus is available commercially).
Motor vehicles, which are covered by the specific EMC directives for vehicles (see Table II).
Medical devices covered by the Medical Devices Directive 93/42/EEC or by the IVD Directive (98/79/EC).
Equipment intended for in-flight use in aircraft, covered by Council Regulation (EEC) No. 3922/91 of December 16, 1991.
Maritime equipment, which is covered by Directive 96/98/EC governing navigation and communication electronics.

The following apparatus are excluded from emissions requirements:

Agricultural and forestry tractors, emissions requirements for which are covered by Directive 75/322/EEC, amended by Directive 82/890/EEC (the EMC Directive covers their immunity requirements).

Excluded from immunity requirements are

Nonautomatic weighing instruments, the immunity requirements for which are laid down in Annex I-8(2) of Directive 90/384/EEC (the EMC Directive covers their emissions requirements).
Active implantable medical devices, which are covered by 90/385/EEC.

Determining and Indicating Conformity

Any product that is to be placed on the European market or taken into use in the EU must comply with all applicable EU directives. Compliance is then indicated by CE marking of the product itself or, where that is not feasible, application of the words on the instructions, warranty card, or packaging. The manufacturer or its authorized representative in the EU must draw up and sign a Declaration of Conformity defining the particular directives applied and, where relevant, identifying any standards or procedures used to demonstrate compliance. This declaration must be available to be shown to any national authority within the EU upon request. (Since the words do not indicate the standards or procedures to which compliance refers, buyers, users, system manufacturers, and others may ask for a copy of this declaration.) The manufacturer or its authorized agent must also maintain a technical file on the product for a period of 10 years after the last apparatus has been placed on the market.

Self-certification is the most commonly used route for EMC conformity assessment of apparatus that can be tested wholly to harmonized standards (excluding radio transmitters). For equipment that cannot reasonably be so tested, the TCF route offers another means of demonstrating EMC conformance. The manufacturer creates a TCF, or Technical Construction File, containing documents describing the product's construction, noting significant design features, providing EMC test results, and giving a rationale for its claims of compliance. The TCF must be reviewed and approved/certified by a competent body (CB) within the EU. Manufacturers of radio transmitters must obtain a type-examination certificate from a notified body—a term that refers to those organizations notified to the EU Commission under the EMC Directive for issuing such type-examination certificates. Note that notified bodies are specific to individual directives; thus, a notified body under the Low Voltage Directive may very well not be a notified body under the EMC Directive. Products that require EMC certification are shown in Table III.

EMC Directive (Article 10.5) Radio transmitting devices (type approval/certification by a notified body).

Vehicle Directive Motor vehicles and separate technical units.

Medical Device Directives Certain medical devices (certification by a notified body).

Table III. Products that require EMC certification.

Procedures for Conformity Assessment per the EMC Directive

The EMC Directive, 89/336/EEC, sets out three separate procedures for conformity assessment according to Article 10(1), 10(2), and 10(5).

Article 10(1) describes the procedure to be used in the case of apparatus for which the manufacturer has been able to apply harmonized standards. Article 10(2) addresses those instances in which the manufacturer has not applied harmonized standards or has applied them only in part, or where no suitable standards exist. (Figure 1 graphically charts these first two routes.) Article 10(5) details the specific procedure required for apparatus designed for the transmission of radio communications.

Figure 1. Routes of conformity assessment under the EMC Directive.

When following the route described in Article 10(1) and referring compliance to harmonized standards, the manufacturer or its authorized representative within the EU/EEA is not required to turn to a third party for testing or assessment.

Article 10(2) defines the so-called TCF route, according to which a manufacturer must compile and retain a Technical Construction File (TCF), which is to contain descriptions of the apparatus itself as well as the procedures used to assess conformity according to the essential requirements of the EMC Directive. The TCF must include all EMC information (emissions and immunity) and must comprise the entire basis for the manufacturer's declaration, even in cases where harmonized standards are used only to some extent (e.g., to cover only emissions or immunity). The competent body must assess the TCF and state its approval by means of either a report or a certificate.

Competent bodies as a rule are test laboratories accredited according to EN 45001 or 45011. This criterion makes sense because it means that when it must deviate from testing according to harmonized standards, a CB will have substantial experience to draw on, by virtue of its having tested to such standards. There are, however, some CBs that represent EMC consulting agencies but do not have accredited lab testing facilities of their own.

The TCF Route

The TCF route is commonly used in situations where

No harmonized standard exists that is relevant for the product.
A product has been tested according to a nonharmonized standard—that is, an earlier national standard—whose EMC requirements are deemed to be at least as severe as those contained in the relevant harmonized standard.
A product for which no product standard exists is to be used in a specific environment or in a specific way to which generic standards are not relevant.
A product fails a specific immunity test according to an applicable harmonized standard, but this failure can be considered not relevant with respect to the actual usage of the product.
An apparatus, system, or installation is too large to be tested in a test laboratory as a single unit, or testing is to be performed either on-site or at the manufacturer's premises.
Verification is necessary for variants of a product for which compliance has been shown by testing one or more reference product(s) to harmonized standards.

For systems and installations, it is up to the manufacturer of the system or the person taking the installation into service to ensure that the provisions of the directive are observed and the EMC requirements complied with. Either a system or a modular approach may be used to demonstrate compliance.

The TCF route is thus not required for verifying a system and/or an installation if all subunits and subsystems comply with the EMC requirements (modular approach), presuming that the referenced standards are relevant for intended environments and that installation guidelines are followed. Since the CE mark does not indicate which directives or standards have been referred to, this will need to be covered in the Declaration of Conformity or another document.

To ensure EMC in practice for a complex system or installation, some additional verification of the system/installation as a whole may be needed (system approach). A logical and practical approach for a manufacturer of complex tailored systems to take is first to test one system and then to use the modular approach when modifying the system/installation through the exchange of subunits/subsystems.

In essence, the EMC Directive mandates that components, apparatus, systems, or installations are not to disturb radio and telecommunications equipment or other electrical apparatus when operating as intended, and they must have adequate levels of intrinsic immunity to electromagnetic disturbances to enable such operation.

Verification according to harmonized standards presumes compliance with the requirements of the directive according to Article 10(1). For most manufacturers, this is the route normally used for CE marking of a product. Others, aware of how difficult it is to demonstrate compliance, turn to accredited test houses for their verification/testing, but this is not mandatory, and for manufacturers that produce many product variants or manufacture customized equipment, such outsourcing can result in a huge number of costly tests. In these cases, the TCF route represents a cost-effective solution.

A TCF must contain a technical rationale demonstrating that the product complies with the essential requirements according to the EMC Directive. This rationale is often based either on testing of subassemblies or on full testing of reference objects of worst-case type. Note, however, that it is impossible to ensure that a product does not emit disturbances that might inhibit the ability of radio or telecommunications or other electronic apparatus to function as intended, nor can it be guaranteed that the apparatus itself will be immune to all types of electromagnetic disturbances.

In uncomplicated cases, a client may ask a CB to produce a simple report on its TCF to affirm that the technical rationale conforms with received wisdom and experience concerning EMC. When certifying a TCF with reference to the essential requirements of the directive, a CB must ensure that all supporting evidence is correct.

Note that when it is impossible to assess the EMC performance of a product by means of a technical description alone, the TCF should include test data.

When it is not possible to fully test a piece of equipment according to harmonized standards, in a test lab, one practical way to show compliance is to refer the EMC requirements as far as possible to methods and limits/criteria corresponding to those appearing in harmonized standards. This can be done by comparing the lab procedures and limits/severity levels defined in the standards with conditions present in the actual environment, and then compensating for nonideal circumstances by adding margins to the defined levels. In situ testing of emissions can be effected through conducted measurements using clamp and/or antenna measuring methods. In situ immunity testing can sometimes be performed using a combination of test methods, such as induced RF current testing up to some hundreds of MHz and RF field testing at frequencies up to some GHz.

Existing Harmonized Standards

Product-Family Standards

The first standards under the EMC Directive were not published ("harmonized") until February 19, 1992. The majority were product-family emission standards—that is, they prescribe limits depending primarily upon the nature of the equipment, rather than upon where it is used. Some of these standards do, however, provide Class A and Class B limits to accommodate residential or industrial applications, as shown in Figure 2.

Figure 2. Class A and Class B limits to accommodate residential or industrial applications.

The use of Class A and Class B limits within the EU often differs from FCC usage. Within Europe, Class B emissions limits are frequently imposed upon equipment that, though operating in a commercial or light-industrial environment, is nevertheless connected to an AC mains branch that also serves residential units. This is justified as follows: because conducted interference propagates through the residential AC mains, emissions from all connected sources should be kept to the lower (Class B) limits. This interpretation is popular throughout the EU and has been formalized into a policy of mandatory Class B compliance for all hospital equipment in Sweden and all telecommunications equipment in Norway. The EU interpretation is moving closer to the FCC definitions of Class A (nonresidential) and Class B (residential) devices. The latest version of CISPR 22 (1997) adopts the FCC class definitions, based upon a lack of evidence of interference when the FCC guidelines are used.

Generic Standards

The list of product/product-family standards originally published under the EMC Directive clearly did not cover all of the possible equipment within the scope of the EMC Directive. To cover the remainder, "generic" standards were provided (see Figure 3). The first of these generic standards were published on April 10, 1992. These are to be applied on the basis of the operating environment of the equipment, rather than on the actual type of product involved.

Disturbance	EN 50082-1:1992	EN 50082-1997
ESD	IEC 801-2:1984 8 kV air	IEC 61000-4-2	4 kV contact, 8 kV air
RF Radiated	IEC 801-3:1984 3 V/m, 27–500 MHZ	EN 61000-4-3 ENV 50204:1995	3 V/m, 80–1000 MHz, modulated 80% 3V/m, 900 MHz keyed at 200 Hz
EFT/B	IEC 801-4:1988 1 kV, 500 V	EN 61000-4-4	1 kV, 500 V
Surges	—	EN 61000-4-5	2 kV line-earth, 1 kV line-line
RF Conducted	—	EN 61000-4-6	3 V, 0.15–30 MHz, modulated
Magnetic Radiated	—	EN 61000-4-8	2 A/m, 50 Hz
Mains Dips and Interruptions	—	EN 61000-4-11	30% dip for 10 ms, 60% for 100 ms, > 95% for 5 s
Figure 3. Original harmonized (left) and newer harmonized (right) CENELEC generic immunity standards. The newer version of EN 50082-1 becomes mandatory July 1, 2001.

For the sake of generic EMC standards, the world is divided into only two types of environments: 1) residential, commercial, and light industrial and 2) industrial. The choice between these two alternatives is largely dictated by whether or not the equipment may share an AC mains source with residential dwellings.

Except for those products covered by a product-family standard containing immunity requirements, all equipment must meet the immunity requirements of either EN 50082-1 or EN 50082-2 (see Table IV). It is important for manufacturers to understand the effects of the electromagnetic disturbances specified in the generic standards and to design their products accordingly. At least one-third of all existing products fail to meet the immunity requirements of the generic standards on their first testing. Significantly, these standards have been revised to meet today's more stringent demands. Among other changes to EN 50082-1:1997, the frequency range for immunity against radiated fields has been raised to 1 GHz, added to which there is now, as in EN 50082-2:1995, a requirement to test with modulated fields (in practice, a much more severe requirement!).

It is equally important for manufacturers to understand the performance criteria specified in the generic standards. During the application of the RF disturbances, the equipment under test must continue to operate as intended (see Table IV, criterion a). During the transient testing, the equipment may malfunction (without loss of data), but it must recover fully without operator intervention after the disturbances cease (see Table IV, criterion b). There is some leeway in how the manufacturer may define these criteria as they relate to the tested product, but that performance should be clearly defined in the equipment description.

Harmonics and Flicker

Emissions

The scope of regulation of low-frequency harmonic emissions and fluctuations was broadened substantially with the publication of EN 61000-3-2:1995 and EN 61000-3-3:1994 in the Official Journal on September 16, 1995. These standards supersede the earlier EN 60555-2 and EN 60555-3. Whereas the '555 standards governed only residential equipment, the newer versions cover all apparatus drawing less than 16 A per phase, whether the apparatus is intended for residential, commercial, or industrial environments.

There has been some controversy concerning the applicability of EN 61000-3-2 and -3-3. Because they were published without an explicit phase-in period, they came into force on January 1, 1996, with the EMC Directive. Their impact will be enormous, with almost all AC-powered equipment being affected. To give manufacturers time to adapt their product designs to conform with the new requirements, CENELEC has reached an agreement with the European Commission to publish a transition period lasting until January 1, 2001, for products not previously covered by these standards.

Under EN 61000-3-2, the limits and product categories of EN 60555-2 are refined and expanded. The absolute harmonic-current limits for power tools and other simple equipment remain unchanged from EN 60555-2, but new categories have been created for lighting devices and for equipment with narrow current peaks of waveform. For these, EN 61000-3-2 limits both the absolute harmonic current and the harmonic current as a percentage of either fundamental current or total power. The percentage limits become important for apparatus that consume several hundred watts of power and have substantial harmonic currents. Numerous industry groups both within the EU and outside it are lobbying for relief from the stringent requirements of EN 61000-3-2 and -3-3.

Other standards having broad applications that were harmonized in 1999 include the following:

EN 55024: 1998—Immunity for ITE.
EN 61326: 1998—EMC for laboratory measurement and control equipment.

EN 61326 contains both emissions and immunity limits with differences for three environments (controlled, industrial, and portable). The standard is similar in its immunity requirements to EN 50082-1:1997 (see Table IV).

Medical Devices

Three New Approach directives are devoted specifically to the safety of medical equipment: 90/385/EEC for active (i.e., electrically powered) implantable medical devices (AIMD), Medical Devices Directive (MDD) 93/42/EEC, and 98/79/EC for in vitro diagnostic medical devices. These are "specific" directives that are exempt under the provisions of the EMC Directive (Article 2). However, they do contain general EMC guidelines. The AIMD has been in full effect since January 1, 1995.

An EMC standard for medical devices has been ratified by both the IEC (IEC 601-1-2:1993) and CENELEC (EN 60601-1-2: 1993); it has been published to the MDD Directive.

As product standards are developed for specific types of medical equipment, they will contain unique EMC requirements that will overrule EN 60601-1-2.

Note that self-certification of the final product is not permitted for devices covered by the AIMD or for most classes of products defined in the MDD (though Class I devices may be self-
certified). Notified body approvals are required for the product, the manufacturer's quality system, or both.

Telecommunications Equipment

The scope of Telecommunications Terminal Equipment Directives 91/263/EEC, 98/13/EC, and 1999/5/EC covers functional, safety, and EMC aspects. It references the EMC Directive for parameters not specific to telecom equipment. An amendment to EN 55022 adds limits for disturbances to telecom ports.

Several wire-line telecom EMC standards are under development by ETSI. One wire-line telecom EMC standard has been harmonized: ETS 300 386-2: 1997. This covers telecommunications network equipment and includes a number of emission and immunity tests as well as operating mode specifications.

Radio Equipment

Under the EMC Directive, the role of a notified body is to issue a type-examination certificate for radio transmitters, except for home-built amateur radio equipment, which is exempt from this directive. In addition to this, there is a need for a radio transmitting approval. This has to be applied for in each Member State, since radio laws have yet to be harmonized. Frequency allocations, operating power, and many other technical details associated with radio transmitters may all vary from country to country. Newer technologies such as GSM cellular radio, DECT digital cordless phones, and pan-European paging systems are, however, being unified. Older radio standards are administered differently in each country.

ETSI has contributed to the transmitter-harmonization process by formulating a series of standards applicable to the noncommunications RF characteristics of radio equipment—that is, EMC characteristics separate from the fundamental output frequency and power.