EMC product standards

Just like most products, virtually all electrotechnical equipment must be tested. More often than not, whether for overall or functional safety, portability, or other reasons, electrotechnical products must be assessed and certified as conforming to specific standards.

When it comes to defining the specific electromagnetic requirements and test procedures, the IEC develops two types of EMC product standards:

  • Stand-alone EMC publications that are particularly appropriate for complex products or those that operate in a special environment; and 
     
  • General product standards that incorporate EMC clauses. This second type is more suitable for products of a simpler nature and is sometimes prepared as an amendment to an existing standard.

What is an EMC product family standard?

Product families

EMC product standards may apply either to particular products, such as electricity meters and printed circuit boards or to a group of products that have common general characteristics, that may operate in the same environment and have neighbouring fields of application. Medical devices, IT equipment (ITE) and low-voltage household equipment are examples of such groups. These publications are known as EMC product family standards.

If the field of application is particularly wide, covering the scope of several IEC product committees, it will be developed by one of the 'horizontal' committees. The IEC Advisory Committee on Electromagnetic Compatibility (ACEC) maintains a list of all the main product families covered by IEC EMC Standards.

EMC product family standards:

Note: The following product family standards and technical reports constitute an important general reference and play a similar role to that of basic EMC publications. With the exceptions of IEC 61000-3-4 to -8 included, they are all referenced in generic and EMC product standards.

Emission

IEC 61000-3-2
Electromagnetic compatibility (EMC) - Part 3-2: Limits - Limits for harmonic current emissions (equipment input current ≤16 A per phase)

IEC 61000-3-3
Electromagnetic compatibility (EMC) - Part 3-3: Limits - Limitation of voltage changes, voltage fluctuations and flicker in public low-voltage supply systems, for equipment with rated current ≤16 A per phase and not subject to conditional connection

IEC/TS 61000-3-4
Electromagnetic compatibility (EMC) - Part 3-4: Limits - Limitation of emission of harmonic currents in low-voltage power supply systems for equipment with rated current greater than 16 A

IEC/TS 61000-3-5
Electromagnetic compatibility (EMC) - Part 3-5: Limits - Limitation of voltage fluctuations and flicker in low-voltage power supply systems for equipment with rated current greater than 75 A

IEC/TR 61000-3-6
Electromagnetic compatibility (EMC) - Part 3-6: Limits - Assessment of emission limits for the connection of distorting installations to MV, HV and EHV power systems

IEC/TR 61000-3-7
Electromagnetic compatibility (EMC) - Part 3-7: Limits - Assessment of emission limits for the connection of fluctuating installations to MV, HV and EHV power systems

IEC 61000-3-8
Electromagnetic compatibility (EMC) - Part 3: Limits - Section 8: Signalling on low-voltage electrical installations - Emission levels, frequency bands and electromagnetic disturbance levels

IEC 61000-3-12
Electromagnetic compatibility (EMC) - Part 3-12: Limits - Limits for harmonic currents produced by equipment connected to public low-voltage systems with input current > 16 A and ≤ 75 A per phase

CISPR 11
Industrial, scientific and medical equipment - Radio-frequency disturbance characteristics - Limits and methods of measurement (0,15-30 MHz)

CISPR 14-1
Electromagnetic compatibility - Requirements for household appliances, electric tools and similar apparatus - Part 1: Emission (0,15-30 MHz and clicks)

CISPR 22
Information technology equipment - Radio disturbance characteristics - Limits and methods of measurement (0,15-30 MHz)

CISPR 11
Industrial, scientific and medical equipment - Radio-frequency disturbance characteristics - Limits and methods of measurement (30-1 000 MHz)

CISPR 14-1
Electromagnetic compatibility - Requirements for household appliances, electric tools and similar apparatus - Part 1: Emission (30-1 000 MHz)

CISPR 22
Information technology equipment - Radio disturbance characteristics - Limits and methods of measurement (0,15-30 MHz)

Who is developing what?

With some 50 technical committees and subcommittees preparing and publishing EMC product standards, the IEC offers the widest global coverage of EMC standardization questions.

Several international, regional, national and professional organizations also refer to or publish EMC product standards. Those include for example ISO (International Organization for Standardization), OIML (International Organization of Legal Metrology), ETSI (European Telecommunications Standards Institute), CENELEC (European Committee for Electrotechnical Standardization), ANSI (American National Standards Institute), FCC (US Federal Communications Commission) and Ecma International, all of which have official liaisons with the IEC.

Product categories

The IEC has found it most practical and convenient to distinguish four product categories for EMC standardization purposes:

Components

These are units that do not themselves have a final function but which are intended for inclusion in an apparatus (see the next category). They may be passive, like resistors, capacitors or integrated circuits, or active like power supply units and certain types of motors.

EMC product standards may be developed for some components, particularly active ones, and these may serve for certification purposes.


Systems
 

In the EMC context, these are combinations of apparatus and/or components constituting a single functional unit intended to be installed and operated to perform a specific task. A good example is a computer system comprising a CPU, monitor, keyboard, mouse, printer, etc.

In this case, and in particular, to ensure "internal" or intra-system compatibility, separate EMC standards may be developed for each component or apparatus. To ensure "external" compatibility with other systems in the same location, and for certification purposes, an overall EMC standard for the whole system may be considered.

Apparatus

These are single finished products with a direct function and intended for final use, such as domestic appliances, medical equipment, tools and circuit-breakers. In principle, EMC product standards must be developed for all such apparatus and, again, these standards may serve for certification purposes.


Installations
 

Again in the EMC context, these are combinations of components, apparatus and systems assembled or erected in a given area, such as industrial plants, electricity substations or telecontrol systems for large areas.

If a set of units is dispersed over a wide area, this clearly may pose problems for emission measurement and immunity testing, and in practice, it may not even be possible to test an installation as a whole unit.

If emission limits are set for the whole installation, as they sometimes are, measurements of harmonics or radio-frequency disturbances, for example, may have to be carried out in situ. In other cases, in particular, for immunity, EMC requirements must be specified for each item and the suppliers of these items must then indicate the installation conditions for their products (such as earthing or wiring) that ensure the whole installation can function properly.

The complete EMC product standard

Because virtually every type of electrical or electronic product requires its EMC performance to be assessed at one time or another in its life, the IEC takes a highly systematic approach in building up its EMC standardization system.
All the detailed guidelines on how to draft EMC publications are contained in IEC Guide 107.
If you are an expert already working on standardization in the IEC, you can download it free of charge. If not, it can be purchased from the IEC Webstore. You can also download a free short introduction to Guide 107 in PDF format.

 

Reference to basic EMC standards

EMC product standards look at both emissions and immunity in the light of every kind of disturbance relevant to the product in its given environment. The product committees developing these publications should refer to the basic EMC standards as far as possible and, in particular, they must not allow higher emission levels than those specified in the generic emission standards or in an applicable EMC product family standard.

On the other hand, they are in principle free to specify their own immunity requirements and test levels, although again preferably applying the test methods and values in the relevant basic EMC standards so that standardized test equipment can be used which is most cost-effective.

Where these restrictions cause difficulties, product committees should discuss the issues with the relevant committee that has 'horizontal' functions, in this case usually IEC TC 77 or CISPR.

 

Comprehensive coverage

Every complete EMC product standard should thus be comprehensive in its coverage and include:

  • The scope of the publication, indicating the type or types of a product covered, the emission and/or immunity problems dealt with and the frequency range(s) in consideration. 
  • A list of all the basic, generic and EMC product family standards to which reference is made in the publication. 
  • A general product specification showing its purpose, users, etc, and indicating any exclusions. 
  • A description of the operation and function of the product including details of the power supply, conditions of use, etc. 
  • A specification of the EM environment in which the product is installed. This is generally taken from the IEC 61000-6-X generic EMC standard but it may also include extra information about special sources of EM disturbances and their levels, for example. 
  • Any special requirements, such as safety requirements, narrow ranges of deviation or performance as a function of time. 
  • The emission limits and test set-up for the relevant low-frequency and high-frequency phenomena. 
  • The immunity requirements and tests, paying particular attention to precise acceptance criteria and preferably providing additional information on which functions should continue to operate and which may be interrupted. 
  • Overview tables summarizing the prescribed emission or immunity tests.