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EMC Standards

EMC standards define terms, rules, test methods, emission limits and immunity levels for Electromagnetic Compatibility (EMC). In the chapters below, you will find an up-to-date overview and some in-depth information about EMC standards. 
This page is thought as free education for those of you out there who have to deal with EMC and product compliance. Please be aware that this website does not dispense you from reading the EMC standards by yourself, as the data on this website are just extracts from the EMC standards and without guarantee.




1  EMC Standards Introduction

Find here an introduction to EMC standards and norms:

What are EMC Standards?

EMC standards and norms define terms, rules and test methods for EMC. Furthermore, they specify limits and minimum test levels for electric and electromagnetic emissions and immunity of electromechanical and electronic products. The following picture shows the most commonly used EMC standards for a consumer electronic product, <16A/phase, which does not have any wireless communication functionality (meaning: all RF emissions are unintended).

Common EMC standards for compliance



Why do we need EMC Standards?

EMC standards help to make measurements comparable and repeatable by defining the test methods, the test equipment and the test environment. And an important point about EMC standards: they have the purpose of bringing harmonization to EMC testing, in the best case: a global harmonization.

Who writes EMC Standards?

Standards in EMC are either defined and worded by international and national or regional organizations and committees on behalf of administrative bodies (like the EU delegates the wording of EMC Standards to CENELEC), or the administrative and/or regulatory bodies word the EMC Standards and regulations themselves.

Here an overview of international and national (regional) organizations and committees which develop and/or define the applicable EMC standards:

What types of EMC Standards are there?

It is to be distinguished between the following classes or types of EMC standards::

  • Basic EMC Publications. The Basic EMC Publications specify the terms and conditions for EMC testing, they define the rules necessary for achieving electromagnetic compatibility, they specify test methods (testing techniques, test setup, test equipment and environment) and so on. Basic EMC Publications are the EMC standards to which other EMC standards (EMC Product Standards, Generic EMC Standards etc.) refer to. You find a list of basic EMC publications - published by the IEC: link.
    Basic EMC publications can be grouped:

    • General. Guidance on how to draft an EMC publication, definition of the EMC terminology and vocabulary, general considerations. Examples: IEC Guide 107, IEC 60050-161, IEC TR 61000-1-1 etc.

    • Environment. Classification and description of different electromagnetic environments and compatibility levels. Examples: IEC TS 61000-2-5, IEC TR 61000-2-3, etc.

    • Emission. Definition of test setups, testing techniques, test equipment, test environment and other considerations regarding EMC emission testing and measurement. Examples: IEC 61000-4-7, IEC 61000-4-14, CISPR 16, etc.

    • Immunity. Definition of test setups, testing techniques, test equipment, test environment and other considerations regarding EMC immunity testing. Examples: IEC 61000-4-1, IEC 61000-4-2, IEC 61000-4-3, etc.

    • Installation/Mitigation. Installation and mitigation guidelines regarding earthing and cabling, mitigation of external electromagnetic influences, HEMP protection concepts and so on. Examples are IEC TR 61000-5-1, IEC TR 61000-5-2, etc.

  • EMC Product Standards. The EMC Product Standards apply to particular products, such as electric road vehicles or coaxial cables. EMC Product Standards refer to the relevant basic EMC publications (for that particular product) and specify the limits of emission and immunity (the minimum test levels). Examples of EMC Product Standards are IEC 62104 (DAB receivers), IEC 61851-21 (electric road vehicles charging system), IEC 62599-2 (alarm end electronic security systems), etc. There is also a list of EMC Product Standards - published by the IEC: link.

  • EMC Product Family Standards. The EMC Product Family Standards apply to a group of products that have common general characteristics, that may operate in the same environment and have neighboring fields of application. EMC Product Family Standards refer to the relevant basic EMC publications (for that particular product) and specify the limits of emission and immunity (the minimum test levels).
    Examples of EMC Product Family Standards are e.g. CISPR 11 (EN 55011, emission) and CISPR 32 (EN 55032, emission). Another example of an EMC Product Family Standard is the family around IEC 61326 (electrical equipment for measurement, control and laboratory use, immunity).There is also a list of product families - published by the IEC:

  • Generic EMC Standards. The Generic EMC Standards are for products operating in a particular EMC environment (residential/industrial), where there does not exist a specific Product (Family) EMC Standard. They are general and somewhat simplified EMC Product Standards, while referring to Basic EMC Publications for detailed measurement and test methods. Generic EMC Standards specify a limited number of essential emission and immunity tests, as well as minimum test levels.
    Examples of Generic EMC Standards are for residential/commercial environments the IEC 61000-6-3 (emission) and IEC 61000-6-1 (immunity) and for industrial environments the IEC 61000-6-4 (emission) and IEC 61000-6-2 (immunity). You can find a list of Generic EMC Standards developed by the IEC TC77 and CISPR here: link.

EMC standards overview



Which EMC Standards to apply for compliance?

This is a tricky part! ​As we mention on the page EMC Compliance, the applicable standards are defined by the responsible governmental administrations, organizations, commissions or committees. So the process of finding the applicable standards often differs from country to country. However, to give you an idea how it works e.g. in the European Union (directive 2014/30/EU), we drew a flow-chart, which is based on the EMCD Guide. Other useful tips:

  • Have a look at the CISPR Guide and search for your product category.

  • Check which EMC standards your competitors applied.

  • Ask your EMC test laboratory for advice which EMC standards to apply.

How to find the right EMC standards.
1 Introduction
What are EMC Standards
Why do we need EMC Standards
Who writes EMC Standards
What types of EMC Standards are there
Which EMC Standard to apply for compliance
2 Global Standards

2  Global EMC Standards

EMC emission and immunity standards are developed to specify terms, measurement methods, limits for conducted and radiated electromagnetic emissions and level of minimum immunity (susceptibility).

We try to give you here an up-to-date overview on the most important international Basic, Generic and Product EMC Standards. On an international level, the EMC standards are developed and published by the International Electrotechnical Commission (IEC).

The following committees have the lead:

The following diagram gives you a little bit of a background about the IEC organization:

IEC organization diagram

In most cases, the national or regional EMC standards are just a "copy" of the international EMC standards, which makes sense, of course (keeping trade barriers low). However, it always takes time until the national and multi-national organizations have adapted to the newest EMC standards released by the IEC. This means that the newest standards and their test methods, limits and test levels may not apply in the country where you would like to distribute and sell your product. So please always check by yourself which EMC standards are applicable for your product and use our lists just as quick reference. If you find outdated information in our list, please let us know:

The basic EMC publications and the generic EMC standards (IEC 61000-6-*) are structured like shown below.

  • IEC 61000

    • Part 1: General (61000-1-*)

      • Basic concepts (fundamental principles, definitions, terminology) - interference model​

      • Functional Safety (what a safety function does and approaches of it being performed satisfactorily)

      • Measurement uncertainty

    • Part 2: Environment (61000-2-*)​

      • Description of the environment​

      • Classification of the environment

      • Compatibility levels

    • Part 3: Limits (61000-3-*)​

      • Emission limits​

      • Immunity limits (insofar as they do not fall under the responsibility of product committees)

    • Part 4: Testing and measurement techniques (61000-4-*)​

      • Measurement techniques​ (without specifying limits)

      • Testing techniques(without specifying limits)

    • Part 5: Installation and mitigation guidelines (61000-5-*)

      • Installation guidelines​

      • Mitigation methods and devices

    • Part 6: Generic Standards (61000-6-*)​

      • ​Generic emission and immunity requirements for residential / commercial and light-industrial environments (limits and minimum test levels)

      • Generic emission and immunity requirements for industrial environments (limits and minimum test levels)

    • Part 9: Miscellaneous (61000-9-*)​

  • CISPR 1​6

    • CISPR 16-1: Consists of six parts, specifies voltage, current and field measuring apparatus and test sites. These include calibration and verification aspects of measuring apparatus.

      • Part 1-1: Measuring apparatus​

      • Part 1-2: Ancillary equipment – Conducted disturbances

      • Part 1-3: Ancillary equipment – Disturbance power

      • Part 1-4: Ancillary equipment – Radiated disturbances

      • Part 1-5: Antenna calibration test sites for 30 MHz to 1 000 MHz

      • Part 1-6: EMC-antenna calibration

    • CISPR 16-2:​ Consists of five parts and specifies the methods for measuring high-frequency EMC phenomena, dealing both with disturbances and immunity.

      • Part 2-1: Conducted disturbance measurements

      • Part 2-2: Measurement of disturbance power

      • Part 2-3: Radiated disturbance measurements

      • Part 2-4: Immunity measurements

      • Part 2-5: In situ measurements for disturbing emissions produced by physically large equipment

    • CISPR 16-3: ​Is an IEC Technical Report (TR) that contains specific technical reports and information on the history of CISPR.

    • CISPR 16-4: Consists of five parts and contains information related to uncertainties, statistics and limit modelling.

      • Part 4-1: Uncertainties in standardized EMC tests​

      • Part 4-2: Uncertainty in EMC measurements

      • Part 4-3: Statistical considerations in the determination of EMC compliance of mass-produced products

      • Part 4-4: Statistics of complaints and a model for the calculation of limits

      • Part 4-5: Conditions for the use of alternative test methods


REMARK: The Basic EMC Standards like IEC 61000-4-* and CISPR 16-*-* do not specify emission limits and/or minimum immunity test levels. In fact, these basic EMC publications describe how the measurement has to be performed, whereas the generic EMC standards and product (family) EMC standards do specify limits and test levels and refer to these basic EMC publications for test setup and methods specification.

In the tables below, you can find:

All tables are also available as XLS and PDF document (XLS and PDF icon).

NOTE: In 2017, CISPR 13 and CISPR 22 were replaced by CISPR 32. However, not all national EMC directives and regulations have been adapted to CISPR 32 yet.

EMC Product Standard List
Generic EMC Standard List
Basic EMC Standards and Publications
EMC Product Standards
Generic EMC Standards
Basic EMC Publications

3  EU EMC Standards

The European Union (EU) EMC Standards are closely related to the international EMC standards and they start with the letters EN, which stands for European Norm. EN standards are developed by CENELEC, CEN, ETSI and are in general harmonized with the international IEC/CSPR standards.

  • European Standardisation Organisations (CEN, CENELEC, ETSI) publish standards and their date of withdrawal (DOW).

  • The EU publishes (via its Official Journal (OJEU)) which EMC standards have to apply for the presumption of conformity.
    IMPORTANT: The date of withdrawal (DOW) of an EMC standard (published e.g. by CENELEC) is not legally binding. The legally binding date where an EMC standard loses its status of presumption of conformity (POC) is the date of cessation (DOC), published by the EU via OJEU.

Here is a list of the most commonly applied European EMC standards and their corresponding IEC/CISPR standards:

Emission [test methods]:

Immunity [test methods]:

Generic standards [emission limits, immunity levels]:

3 EU Standards
4 US Standards

4  US EMC Standards

Here is an overview on United States EMC standards:

FCC Regulations and IEEE/ANSI EMC Standards.

The Code of Federal Regulations (CFR), Title 47 (Telecommunications), Chapter I (Federal Communication Commission) contains the following parts, which can be seen as the United States (US) EMC regulations:

One difference between the US regulations and the EU regulations is, that the US regulations (FCC, Title 47, Chapter I) do also specify the limits in the law, e.g. here for the conducted limits of unintentional radiators 47 CFR 15.107. Whereas in the EU laws and directives, this is not the case and the test limits are specified in the EMC Standards, issued by the IEC/CISPR organizations. On the other side, the methods of testing for the US, are mostly specified by the IEEE Standards Organization. Here the most important EMC Standards for the US:

  • IEEE/ANSI C63.4 American National Standard for Methods of Measurement of Radio-Noise Emissions from Low-Voltage Electrical and Electronic Equipment in the Range of 9 kHz to 40 GHz.
    ANSI C63.4, conducted emission testing, conducting ground plane, digital equipment, electric field measurement, line impedance stabilization network, low-voltage electrical equipment, low-voltage electronic equipment, magnetic field measurement, normalized site attenuation, radiated emission testing, radio-noise emissions, radio-noise power, site attenuation, unintentional radiators.

  • IEEE/ANSI C63.10 American National Standard of Procedures for Compliance Testing of Unlicensed Wireless Devices.
    The procedures for testing the compliance of a wide variety of unlicensed wireless transmitters (also called intentional radiators and license-exempt transmitters) including, but not limited to, remote control and security unlicensed wireless devices, frequency hopping and direct sequence spread spectrum devices, antipilferage devices, cordless telephones, medical unlicensed wireless devices, Unlicensed National Information Infrastructure (U-NII) devices, intrusion detectors, unlicensed wireless devices operating on frequencies below 30 MHz, automatic vehicle identification systems, and other unlicensed wireless devices authorized by a radio regulatory authority are covered in this standard. Excluded by this standard are test procedures for unlicensed wireless devices already covered in other published standards (e.g., Unlicensed Personal Communication Services (UPCS) devices).

  • IEEE/ANSI C63.15 American National Standard Recommended Practice for the Immunity Measurement of Electrical and Electronic Equipment.
    This immunity testing and test instrumentation specifications recommended practice complements the procedures for making emission measurements as specified in ANSI C63.4 and in ANSI C63.10. These immunity test methods can be used by manufacturers who want to maximize product reliability and reduce customer complaints by improving the immunity of their products, beyond that required by applicable regulations, or by correcting problems experienced in deployment that are not related to regulatory requirements. This recommended practice generally covers the frequency range of 30 Hz to 10 GHz.

  • IEEE/ANSI C63.17 American National Standard Methods of Measurement of the Electromagnetic and Operational Compatibility of Unlicensed Personal Communications Services (UPCS) Devices.
    Specific test procedures for verifying the compliance of unlicensed personal communications services (UPCS) devices (including wide-band voice and data devices) are established including applicable regulatory requirements regarding radio-frequency emission levels and spectrum access procedures.

  • FCC MP-5-1986 Methods of measurement of radio noise emissions from Industrial, Scientific and Medical (ISM) equipment).

NOTE: As of today [2019], the FCC CFR 47 do only specify emission limits and no immunity test levels. However, it is only a matter of time, until the FCC does also specify susceptibility/immunity.

US Military EMC Standards.

Here are the two most important United States Department of Defense (DoD) EMC standards:

  • MIL-STD-461. Requirements for the Control of Electromagnetic Interference Characteristics of Subsystems and Equipment.

  • MIL-STD-464. Electromagnetic Environmental Effects (E3) Requirements for Systems.

Both US military EMC standards are applicable in the fields of

  • Army

  • Aviation (Army and Navy aircraft, Air Force)

  • Aerospace

  • Marine (ships and submarines)

MIL-STD-461 is the United States Department of Defense EMC standard for modules and/or subsystems. MIL-STD-461 contains emission and immunity requirements. Unlike FCC or IEEE/ANSI standards, MIL-STD-461 is not a legally binding EMC standard. MIL-STD-461 is a contractual standard, where test limits and emission levels can be negotiated and waivers are possible.

This standard is best suited for items that have the following features: electronic enclosures that are no larger than an equipment rack, electrical interconnections that are discrete wiring harnesses between enclosures, and electrical power input derived from prime power sources. MIL-STD-461 should not be directly applied to items such as modules located inside electronic enclosures or entire platforms. The principles in MIL-STD-461 may be useful as a basis for developing suitable requirements for those applications.

MIL-STD-461 contains the following emission and susceptibility requirements.

  • CE = Conducted Emission

    • CE101. Audio frequency currents, power leads. 30Hz to 10kHz.

    • CE102. Radio frequency potentials, power leads. 10kHz to 10MHz.

    • CE106. Antenna Port. 10kHz to 40GHz.

  • CS = Conducted Susceptibility

    • CS101. Power leads. 30Hz to 150kHz.

    • CS103. Antenna port, intermodulation. 15kHz to 10GHz.

    • CS104. Antenna port, rejection of undesired signals. 30Hz to 20GHz.

    • CS105. Antenna port, cross-modulation. 30Hz to 20GHz.

    • CS109. Structure current. 60Hz to 100kHz.

    • CS114. Bulk cable injection. 10kHz to 200MHz.

    • CS115. Bulk cable injection, impulse excitation.

    • CS116. Damped sinusoidal transients, cables & power leads. 10kHz to 100MHz.

    • CS117. Lightning induced transients, cables & power leads.

    • CS118. Personnel borne electrostatic discharge. 8kV contact discharge.

  • RE = Radiated Emission

    • RE101. Magnetic field. 30Hz to 100kHz.

    • RE102. Electric field. 10kHz to 18GHz.

    • RE103. Antenna spurious and harmonic outputs. 10kHz to 40GHz.

  • RS = Radiated Susceptibility

    • RS101. Magnetic field. 30Hz to 100kHz

    • RS103. Electric field. 2MHz to 40GHz.

    • RS105. Transient electromagnetic field.

The MIL-STD-461 standard can be downloaded for free by clicking on the .pdf icon below.

MIL-STD-464 is the United States Department of Defense EMC standard which establishes electromagnetic environmental effects (E3) interface requirements and verification criteria for airborne, sea, space, and ground systems, including associated ordnance. MIL-STD-464 is applied at system or platform level.

US Airborne Equipment EMC Standards.

RTCA DO-160 contains Environmental Conditions and Test Procedures for Airborne Equipment and is the minimum standard for the environmental testing of commercial avionics hardware. It is published by the Radio Technical Commission for Aeronautics (RTCA). The following sections of DO-160 are related to EMC:

  • 15 Magnetic Effect (effect of on-board equipment to compass)

  • 16 Power Input (conducted emissions and susceptibility)

  • 17 Voltage Spike (susceptibility of equipment at AC or DC power leads)

  • 18 Audio Frequency Conducted Susceptibility - Power Inputs

  • 19 Induced Signal Susceptibility (susceptibility of equipment on induced voltages)

  • 20 Radio Frequency Susceptibility (radiated and conducted)

  • 21 Emission of Radio Frequency Energy (radiated and conducted)

  • 22 Lightning Induced Transient Susceptibility (indirect lightning effects)

  • 23 Lightning Direct Effects (limited to equipment mounted on the exterior aircraft)

  • 25 Electrostatic Discharge (for equipment accessible during operation and service)


The European Organization for Civil Aviation Equipment (EUROCAE) works jointly with RTCA in the development of standards and publishes an identical standard called EUROCAE ED-14D.

5 Emission

5.1  CISPR 11

The IEC/CISPR 11, EN 55011 (Industrial, scientific and medical (ISM) radio-frequency equipment – Electromagnetic disturbance characteristics – Limits and methods of measurement) is about: Conducted and radiated emissions of signals in the frequency range of 9kHz to 400GHz.


Equipment covered by other CISPR product and product family emission standards are excluded from the scope of CISPR 11. CISPR 11 applies to industrial, scientific and medical electrical equipment operating in the frequency range 0Hz to 400GHz and to domestic and similar appliances designed to generate and/or use locally radio-frequency energy. CISPR 11 standard covers emission requirements related to radio-frequency (RF) disturbances in the frequency range of 9kHz to 400GHz. Measurements need only be performed in frequency ranges where limits are specified.

CISPR 11 and CISPR 14: Induction cooking is the scope of CISPR 14-1 and CISPR 14-2 [May-2019]. Microwave ovens are primarily the scope of CISPR 11 and CISPR 14-2 (however, be aware of multi-function equipment which may also be the scope of CISPR 14-1, e.g. for click measurement).

For ISM Radio-Frequency (RF) applications in the meaning of the definition found in the United Nations specialized agency for information and communication technologies (ITU) Radio Regulations, CISPR 11 covers emission requirements related to radio-frequency disturbances in the frequency range of 9kHz to 18GHz. Requirements for ISM RF lighting equipment and Ultra Violet (UV) radiators operating at frequencies within the ISM frequency bands defined by the ITU Radio Regulations are contained in CISPR 11.

In the following, the term ISM band often appears (also in the FCC Part 18 section). In order to clarify things, here are some facts:

  • The industrial, scientific and medical (ISM) radio bands are reserved internationally for the use of radio frequency (RF) energy for industrial, scientific and medical purposes other than telecommunications.

  • ISM bands are defined by the ITU Radio Regulations (article 5) in footnotes 5.138, 5.150, and 5.280 of the Radio Regulations.

  • Not all ISM frequency bands are harmonized worldwide. Some apply only to certain regions (see below).

ISM frequency bands by ITU
ISM regions defined by ITU


There are two groups of ISM equipment defined in CISPR 11:

  • Group 1 (general purpose applications, class A or class B): All equipment in the scope of CISPR 11 which is not classified as Group 2 equipment. Examples of Group 1 equipment:

    • Laboratory equipment

    • Medical electrical equipment

    • Scientific equipment

    • Semiconductor-converters

    • Industrial electric heating equipment with operating frequencies less than or equal to 9 kHz

    • Machine tools

    • Industrial process measurement and control equipment

    • Semiconductor manufacturing equipment

    • Switch mode power supplies​

  • Group 2 (ISM RF applications, class A or class B): All ISM RF equipment in which radio-frequency energy in the frequency range 9kHz to 400GHz is intentionally generated and used or only used locally, in the form of electromagnetic radiation, inductive and/or capacitive coupling, for the treatment of material, for inspection/analysis purposes, or for transfer of electromagnetic energy. Examples of Group 2 equipment:

    • Microwave-powered UV irradiating apparatus

    • Microwave lighting apparatus

    • Industrial induction heating equipment operating at frequencies above 9 kHz

    • Dielectric heating equipment Industrial microwave heating equipment

    • Arc Welding equipment

    • Microwave ovens

    • Medical electrical equipment

    • Electric welding equipment

    • Electro-discharge machining (EDM) equipment

    • Demonstration models for education and training​

    • Battery chargers and power supplies – wireless power transfer (WPT) mode


There are two classes of ISM equipment defined in CISPR 11:

  • Class A (higher emission limits, industrial): Class A devices are devices that are suitable for use in all areas other than residential and such areas, and they are connected to the public mains.
    Devices must have emissions which are below the limits of Class A, but the emissions may exceed the limits of Class B.
    For Class A equipment, the instructions for use accompanying the product shall contain the following text: Caution: This equipment is not intended for use in residential environments and may not provide adequate protection to radio reception in such environments.

  • Class B (lower emission limits, residential): Class B devices are devices that are suitable for use in residential areas and such areas, and they are connected to the public mains.

CISPR 11 class and group definition

Test Setup.

Test location:

  • Class A. Class A equipment may be measured either on a test site or in situ (at installation site) as preferred by the manufacturer. Due to size, complexity or operating conditions some equipment may have to be measured in situ in order to show compliance with the radiation disturbance limits.

  • Class B. Class B  equipment shall be measured on a test site.

Measuring distance for radiated emissions:

  • Class A. On a test site, Class A equipment can be measured at a nominal distance d of 3m, 10m or 30m.
    Class A Group 1 equipment can be measured in situ, where the measurement takes place at a distance of 30m from the outer face of the exterior wall of the building in which the equipment is situated.
    Class A Group 2 equipment can be measured in situ, where the measurement distance d from the exterior wall of the building in which the equipment is situated equals (30+x/a)m or 100m whichever is smaller, provided that the measuring distance d is within the boundary of the premises. In the case where the calculated distance d is beyond the boundary of the premises, the measuring distance d equals x or 30m, whichever is longer. For the calculation of the above values:

    • x is the nearest distance between the exterior wall of the building in which the equipment is situated and the boundary of the user’s premises in each measuring direction.

    • a = 2.5 for frequencies lower than 1 MHz.

    • a = 4.5 for frequencies equal to or higher than 1 MHz.

  • Class B. On a test site, Class B equipment can be measured at a nominal distance d of 3m or 10m.

  • < 10m. In the frequency range 30MHz to 1000MHz, a distance less than 10m is allowed only for equipment which complies with the definition for small size equipment. Small size equipment is either positioned on a table top or standing on the floor which, including its cables fits in an imaginary cylindrical test volume of 1.2m in diameter and 1.5m height (to ground plane).

Consistent with typical applications of the equipment under test, the level of the disturbance shall be maximized by varying the configuration of the equipment.

An example of a typical setup for measurements of radiated disturbances from a table-top EUT is given below (top-view). The measurement arrangement shall be typical of normal installation practice and centered to the turntable’s vertical axis.

CISPR 11 radiated emission test setup top view


An example of a typical unified test set up for floor standing equipment suitable for measurement of conducted as well as radiated disturbances is shown below. Further examples of typical arrangements of the EUT and associated peripherals are given in CISPR 16-2-3 and CISPR 16-2-1.


CISPR 11 radiated and conducted emission test setup floor standing

Limits Test Site.

There are limits for conducted and radiated emissions specified in CISPR 11. Below, you can find the limits for measurements performed on a test site (not in situ).

CISPR 11 Group 1 @ Test Site:

CISPR 11 Group 2 @ Test Site:

CISPR 11 Group 1, Group 2, Class A, Class B, Conducted Emission Limits Mains Port
CISPR 11 Class A, Group 1, Conducted Current Emission Limits, DC Power Port
CISPR 11 Group 1 Class A Class B Radiatd Emission Limits
CISPR 11 Group 2 Class A Class B Radiatd Emission Limits

Limits in situ.

Under in situ conditions, an assessment of conducted disturbances is not required.

CISPR 11 Group 1 @ in situ:

CISPR 11 Group 2 @ in situ:

CISPR 1 Group 1 Class A radiated limit for magnetic field in situ
CISPR 1 Group 1 Class A radiated limit for electric field in situ
CISPR 1 Group 2 Class A radiated limit for magnetic field in situ
CISPR 1 Group 2 Class A radiated limit for electric field in situ
CISPR11 150k-30M Mains
CISPR11 150k-30M Gr1 DC Voltage
CISPR11 Gr1 30M-1G
CISPR11 150k-30M Gr1 ClassA DC Current
ISM frequency bands
CISPR11 Gr2 30M-1G

5.2  CISPR 32

The IEC/CISPR 32, EN 55032 (Electromagnetic compatibility of multimedia equipment - Emission requirements) is about: Conducted and radiated emissions of signals in the frequency range of 9kHz to 400GHz. CISPR 32 replaced CISPR 13 and the popular CISPR 22 in March 2017.


CISPR 32 applies to multimedia equipment (MME) and having a rated RMS AC or DC supply voltage not exceeding 600 V. Equipment within the scope of CISPR 13 or CISPR 22 is within the scope of CISPR 32. MME intended primarily for professional use is within the scope of CISPR 32. The radiated emission requirements in CISPR 32 are not intended to be applicable to the intentional transmissions from a radio transmitter as defined by the ITU, nor to any spurious emissions related to these intentional transmissions. Equipment, for which emission requirements in the frequency range covered by CISPR 32 are explicitly formulated in other CISPR publications (except CISPR 13 and CISPR 22), are excluded from the scope of this publication. CISPR 32 does not contain requirements for in-situ assessment (in other words: the tests have to be done in an EMC test laboratory). The objectives of CISPR 32 publication are:

  1. To establish requirements which provide an adequate level of protection of the radio spectrum, allowing radio services to operate as intended in the frequency range 9kHz to 400GHz.

  2. To specify procedures to ensure the reproducibility of measurement and the repeatability of results.

The CISPR 32 is often referenced by other product and product family standards, outside of the scope defined above.


There are two classes of Information Technology Equipment (ITE) defined in CISPR 32:

  • Class A (higher emission limits, industrial): Devices must have emissions which are below the limits of Class A, but the emissions exceed the limits of Class B.
    Class A devices shall have a warning notice in their manual (e.g. "Warning! This is a Class A device. This device may cause radio interference in residential areas; in this case, the operator may be required to take appropriate measures".).

  • Class B (lower emission limits, commercial): Devices must have emissions which are below the limits of Class B. This is applicable for devices which are used in a residual and domestic environment. In other words: commercial devices. E.g.:

    • No permanent location (e.g. battery powered devices)​

    • Telecommunication terminal equipment

    • Personal computers


There are limits for conducted and radiated emissions specified in CISPR 32. You can find them in the pictures below. The limits for quasi-peak AND average must not be exceeded by Class A devices (blue) or Class B devices (orange) respectively.

We also added the radiated emission limits for 3m measurement distance, which are in general 20*10log(10m/3m)=10.5dB higher compared to the specified limits for 10m distance. In case you measure at 1m distance (1m distance between Equipment Under Test (EUT) and antenna), the limits are 20*10log(10m/1m)=20dB higher than the 10m limits.


CISPR 32 Coducted Emission Limits Mains Ports
CISPR 32 Coducted Emission Limits LAN Ports
CISPR 32 Coducted Emission Current Limits LAN Ports
CISPR 32 Radiated Emission 10m vs. 3m. 80MHz - 1GH.
CISPR 32 Radiated Emission 1GHz - 6GHz
CISPR32 CE Mains Ports
CISPR11 G1 ClA M in situ
CISPR11 G1 ClA E in situ
CISPR11 G2 ClA M in situ
CISPR11 G2 ClA E in situ

5.3  IEC 61000-3-2

The IEC 61000-3-2 (Limits for harmonic current emissions - equipment input current ≤16A per phase) is a Basic Standard which deals with the limitation of harmonic currents injected into the public mains supply system. It specifies limits of harmonic components of the input current which can be produced by equipment tested under specified conditions. The objective of IEC 61000-3-2 is to set limits for harmonic emissions of equipment within its scope, so that, with due allowance for the emissions from other equipment, compliance with the limits ensures that harmonic disturbance levels do not exceed the compatibility levels defined in IEC 61000-2-2.
Professional equipment that does not comply with the requirements of IEC 61000-3-2 can be permitted to be connected to certain types of low voltage supplies, if the instruction manual contains a requirement to ask the supply utility for permission to connect. Recommendations concerning this aspect are contained in IEC 61000-3-12.

The following graphic shows an example current curve of a lightning equipment with dimming control. The curve current shows a phase shift and harmonic distortions.

IEC 61000-3-2 Current Distortion Example


IEC 61000-3-2 applies to:

  • Apparatus intended to be connected to public low‑voltage distribution systems (50Hz or 60Hz, 220/380V, 230/400V and 240/415V). For systems with nominal voltages less than but not equal to 220 V (line-to-neutral), the limits have not yet been considered [2019].

  • Apparatus having a rated input current up to and including 16 A per phase.

  • Arc welding equipment which is not professional equipment, with a rated input current up to and including 16A per phase. Arc welding equipment intended for professional use, as specified in IEC 60974-1, is excluded from IEC 61000-3-2 and can be subject to installation restrictions as indicated in IEC 61000-3-12.


There are four classes of equipment defined:

  • Class A: Equipment not specified as belonging to Class B, C or D shall be considered Class A equipment. Some examples of Class A equipment:

    • Balanced three-phase equipment​.

    • Household appliances, excluding those specified as Class B, C or D.

    • Vacuum cleaners.

    • High-pressure cleaners.

    • Tools, excluding portable tools.

    • Independent phase control dimmers.

    • Audio equipment.

    • Professional luminaires for stage lighting and studios.

  • Class B: Portable tools and arc welding equipment which is not professional equipment.

  • Class C: Lighting equipment.

  • Class D: Equipment, having a specified power consumption of less than or equal to 600 W, of the following types:

    • Personal computers and personal computer monitors​.

    • Television receivers.

    • Refrigerators and freezers having one or more variable-speed drives to control compressor motor(s).

Test Setup.

Here an example of a single-phase measurement circuit. The measurement equipment shall be compliant with IEC 61000-4-7 shall be used.

  • S: Power supply source

  • G: Open-loop voltage of the supply source

  • M: Measurement equipment

  • EUT: Equipment under test

  • U: Test voltage

  • Ih: Harmonic component of order h of the line current

  • ZM: Input impedance of measurement equipment

  • ZS: Internal impedance of the supply source

IEC 61000-3-2 Test Setup


For the following categories of equipment are no limits specified in IEC 61000-3-2:

  • Lighting equipment with a rated power <5W

  • Equipment with a rated power of ≤75W, other than lighting equipment

  • Professional equipment with a total rated power >1kW

  • Symmetrically controlled heating elements with a rated ≤200W

  • Certain types of independent phase control dimmers.

Before we have a look at the limits, here two important formulas. According to IEC 61000-3-2, the total harmonic current (THC) is equal the total RMS value of the harmonic current components of orders 2 to 40:

THC Total Harmonic Current IEC 61000-3-2

According to IEC 61000-3-2, the total harmonic distortion (THD) is defined as the ratio of the RMS value of the sum of the harmonic components (in this context, harmonic current components Ih of orders 2 to 40) to the RMS value of the fundamental component I1, expressed as:

THC Total Harmonic Distortion IEC 61000-3-2

IEC 61000-3-2 defines different limits depending on the equipment class.

  • Class A. Limits for Class A equipment are shown in the respective table below.

  • Class B. Limits for Class B equipment are Class A limits multiplied by factor 1.5.

IEC 61000-3-2 Limits Class A

  • Class C

    • Rated power ≥5W and ≤25W.

      • Harmonic currents shall not exceed the power-related limits of Class D (column 2​ in table Class D below).

      • The third harmonic current, expressed as a percentage of the fundamental current, shall not exceed 86% and the fifth harmonic current shall not exceed 61%. In addition, the waveform of the input current shall be such that it reaches the 5% current threshold before or at 60°, has its peak value before or at 65° and does not fall below the 5% current threshold before 90°, referenced to any zero crossing of the fundamental supply voltage. The current threshold is 5% of the highest absolute peak value that occurs in the measurement window, and the phase angle measurements are made on the cycle that includes this absolute peak value. Components of current with frequencies above 9kHz shall not influence this evaluation (a filter similar to the one described in IEC 61000-4-7:2002 may be used).

      • The THD (formula can be found above) shall not exceed 70%. The third-order harmonic current, expressed as a percentage of the fundamental current, shall not exceed 35%, the fifth-order current shall not exceed 25%, the seventh order current shall not exceed 30%, the ninth and eleventh order currents shall not exceed 20% and the second-order current shall not exceed 5%.

    • Rated power >25W.

      • Luminaires. For luminaires with incandescent lamps and built-in phase control dimming having a rated power greater than 25 W, the harmonics of the input current shall not exceed the limits of Class A equipment.

      • Any other lightning equipment. For any other lighting equipment having a rated power greater than 25 W, the harmonics of the input current shall not exceed the relative limits specified for Class C in the table below.​

IEC 61000-3-2 Limits Class B

  • Class D. Limits for Class D equipment is shown in the table below.

IEC 61000-3-2 Limits Class D

5.4  IEC 61000-3-3

The IEC 61000-3-3 (Limitation of voltage changes, voltage fluctuations and flicker in public low-voltage supply systems, for equipment with rated current ≤16A per phase and not subject to conditional connection) is a Product Family Standard which is concerned with the limitation of voltage fluctuations and flicker impressed on the public low-voltage system. It specifies limits of voltage changes that may be produced by equipment tested under specified conditions and gives guidance on methods of assessment.

The definition of flicker by IEC is as follows: Impression of unsteadiness of visual sensation induced by a light stimulus whose luminance or spectral distribution fluctuates with time. [Source: Electropedia - The World's Online Electrotechnical Vocabulary]

Flicker can be considered as a symptom, resulting from the modulation of a load and its effect on its own terminal voltage. Whilst connected to a voltage source with finite impedance, any load modulation will cause voltage fluctuations on the supply line.


IEC 61000-3-3 is applicable to electrical and electronic equipment having an input current equal to or less than 16A per phase, intended to be connected to public low-voltage distribution systems of between 220V and 250V line to neutral at 50Hz, and not subject to conditional connection.

  • Should a device fail the limits specified in IEC 61000-3-3 tested with the specified source impedance Zref, it may be retested to show conformity with IEC 61000-3-11.  Part 3-11 is applicable to all equipment with rated input ≤75A per phase and is subject to conditional connections.

  • Devices that are unlikely to produce significant voltage fluctuations or flicker do not need to be tested.
    It may be necessary to clarify whether significant voltage fluctuations are generated with a certain probability by evaluating the circuit diagram and the specification of the device and by a short functional test.

  • For power grids with a voltage of less than 220V, and/or with a frequency of 60Hz, the limits and values ​​for reference impedances are still under consideration [2019].

Zref is the internationally agreed reference source impedance for low-voltage supply networks.

Test Setup.

The test setup consists of:

  • G: Voltage Source

  • EUT: Equipment Under Test

  • M: Measuring Equipment

  • S: Supply Source including reference impedance Zref and voltage generator output impedance:

    • RA = 0.24Ω jXA = 0.15Ω @ 50Hz

    • RN = 0.16Ω jXN = 0.10Ω @ 50Hz

IEC 61000-3-3 flicker test setup


First, flicker limits are mainly based on the subjective perception of flicker in the light of 230V / 60W incandescent lamp, which is caused by fluctuations in the supply voltage.

Second, there are some terms to explain:

  • Pst is the calculated short-term flicker as per IEC 61000-4-15, unless otherwise specified the Pst evaluation period is 10 minutes.

  • Plt is the calculated long-term flicker as per IEC 61000-4-15. Unless otherwise specified, the Plt evaluation period is 2 hours (N=12 in the formula below).

IEC 61000-3-3 long ter flicker formula


Commonly known as d values, voltage change characteristics constitute three separate parameters – d(t), dc, dmax.

  • d(t): Time function of the relative root mean square (RMS) half period voltage change for each half period between zero-crossings of the voltage source, expected during steady-state voltage conditions.

  • dc: Maximum steady-state voltage change during an observation period

  • dmax: Maximum absolute voltage change during the observation period

  • Tmax: Maximum time that the half period RMS voltage exceeds the limit for dc. During a voltage change event, the Tmax value is accumulated until a new steady-state condition is established.

The IEC 61000-3-3 limits are as follows:

  • Pst : Short-term flicker value Pst must be less than or equal to 1.0.

  • Plt: Long-term flicker value Plt must be less than or equal to 0.65.

  • d(t), Tmax: Accumulated time of d(t) with a deviation exceeding 3.3% during a single voltage change at the equipment under test terminals must not exceed 500msec.

  • dc: The maximum relative steady-state voltage change dc must not exceed 3.3%.

  • dmax: Maximum relative voltage change (between two half periods) shall not exceed:

    • 4% without additional conditions

    • 6% for equipment that is;

      • switched manually

      • switched automatically more than twice a day and is also fitted with a delayed restart not less than a few tens of seconds. Alternatively a manual restart after a power supply interruption.

    • 7% for equipment that is;

      • attended whilst in use

      • switched on automatically or intended to be switched on automatically no more than twice per day. Must also be fitted with a delayed restart of not less than a few tens of seconds (or manual restart) after a power supply interruption.

IEC 61000-3-3 flicker voltage fluctuation diagrams


The graph below shows the Pst=1-curve. The concept behind this curve: If the performance of the EUT lies under the Pst=1-curve then the disturbance to the supply network is deemed to be acceptable in the short term.

REMARK: 1200 voltage fluctuations per minute lead to a 10Hz flicker.

IEC 61000-3-3 flicker - Pst=1 curve

5.5  IEC 61000-6-3

The IEC 61000-6-3 (Generic standards - Emission standard for equipment in residential environments) is a Generic Standard for emissions (conducted, radiated) in residential environments (indoor and outdoor). The emission requirements cover the frequency range 0Hz to 400GHz.


This generic EMC emission standard is applicable if no relevant dedicated product or product-family EMC emission standard exists. IEC 61000-6-3 applies to:

  • Equipment for which no relevant dedicated product standard or product family Emission standard exists.

  • IEC 61000-6-3 for emission requirements applies to electrical and electronic equipment intended for use at residential locations. IEC 61000-6-3 also applies to electrical and electronic equipment intended for use at other locations that do not fall within the scope of IEC 61000-6-8 or IEC 61000-6-4.

  • The intention is that all equipment used in the residential, commercial and light-industrial environments are covered by IEC 61000-6-3 or IEC 61000-6-8. If there is any doubt the requirements in IEC 61000-6-3 apply.

The generic EMC standard for emissions of equipment that runs in light-industrial locations is IEC 61000-6-8.


The next table shows which basic EMC publications and which emission limits are to apply.

IEC 61000-6-3 limits

5.6  IEC 61000-6-4

The IEC 61000-6-4 (Generic standards - Emission standard for industrial environments) is a Generic Standard for emissions (conducted, radiated) in industrial environments (indoor and outdoor). The emission requirements cover the frequency range 9kHz to 400GHz. 


IEC 61000-6-4 applies to:

  • IEC 61000-6-4 is applicable to equipment that does not fall within the scope of IEC 61000-6-3.

  • Equipment for which no relevant dedicated product standard or product family emission standard exists.

  • Equipment intended for use within the environment existing at industrial locations.


The next table shows which basic EMC publications and which emission limits are to apply.

IEC 61000-6-4 limits
FCC Part 15

5.7  FCC Part 15

The FCC Part 15 is a U.S. EMC Standard. FCC Part 15 is an emission standard (conductive, radiated) for radio frequency devices (intentional and unintentional radiators). FCC Part 15 consists of several subparts. The most applicable subpart of FCC Part 15 is subpart B, because it applies to virtually all digital electronics (exempted devices of FCC 15 subpart B can be found in 47 CFR 15.103).



In order to show compliance with FCC 47 CFR Part 15, the FCC specifies that measurements have to be performed following the procedures described in the EMC Standards (47 CFR 15.31):

  • ANSI C63.4-2014 (unintentional radiators)

  • ANSI C63.10-2013 (intentional radiators)

  • ANSI C63.17-2013 (Unlicensed Personal Communication Services)

  • FCC/OET MP-2 (UHF Noise Figures of TV Receivers)

The EMC tests must be performed with all cables connected and configured in a reasonable way that tends to maximize the emission (47 CFR 15.31, 47 CFR 15.32).


FCC Part 15 is applicable for most electronic devices (hereinafter: radio frequency devices). A radio frequency device is any device that in its operation is capable of emitting radio frequency energy by radiation, conduction, or other means (see 47 CFR 2.801). Radio frequency is defined by the FCC as any electromagnetic energy in the frequency range from 9 kHz to 3000 GHz (see 47 CFR 15.3(u)).​



The digital devices of FCC 47 CFR Part 15 are divided in two classes (like in CISPR 32 and CISPR 11):

  • Class A. A digital device that is marketed for use in a commercial, industrial or business environment, exclusive of a device that is marketed for use by the general public or is intended to be used in the home (47 CFR 15.3(h)).

  • Class B. A digital device that is marketed for use in a residential environment notwithstanding use in commercial, business and industrial environments. Examples of such devices include, but are not limited to, personal computers, calculators, and similar electronic devices that are marketed for use by the general public (47 CFR 15.3(i)).


The conducted emission limits for FCC Part 15 (public AC mains port connection (47 CFR 15.107)) are harmonized with the CISPR limits (commission amending of FCC in 2002).

The radiated emission limits differ from the CISPR limits. However, the FCC released a document which describes the applicability of CISPR limits for FCC 15 subpart B (unintentional radiators) approval.​

The emission limits for FCC 15 subpart B (unintentional radiators) can be found below. The emission limits for all the other subparts of FCC 15 depend on the device's operation band and can be found here: 47 CFR 15. For frequencies up to 1GHz, the resolution bandwidth (RBW) is 120kHz (quasi-peak detector), above 1GHz the RBW has to be set to 1MHz (average detector).

FCC Part 15 Subpart B Limits. 10m vs. 3m.  30-1000MHz.
FCC Part 18
US ISM frequency

5.8  FCC Part 18

The FCC Part 18 is an U.S. EMC Standard. It FCC Part 18 is an emission standard (conductive, radiated) for Industrial, Scientific and Medical Equipment (ISM). FCC Part 18 consists of several subparts:

The methods of measurement for FCC Part 18 are specified in FCC MP-5 (FCC Methods of Measurements of Radio Noise Emissions from Industrial, Scientific, and Medical equipment).


According to 47 CFR 18.107(c), ISM equipment is designed to generate and use locally RF energy for industrial, scientific, medical, domestic or similar purposes, excluding applications in the field of telecommunication. Typical ISM applications are the production of physical, biological, or chemical effects such as heating, ionization of gases, mechanical vibrations, hair removal and acceleration of charged particles. Here a list of ISM equipment:

  • Industrial Heating Equipment (18.107(d)). ISM equipment used for or in connection with industrial heating operations utilized in a manufacturing or production process (RF welders, RF lighting devices).

  • Medical Diathermy Equipment (18.107(e)). ISM equipment used for therapeutic purposes, not including surgical diathermy apparatus designed for intermittent operation with low power.

  • Ultrasonic Equipment (18.107(f)). ISM equipment in which the RF energy is used to excite or drive an electromechanical transducer for the production of sonic or ultrasonic mechanical energy for industrial, scientific, medical or other non-communication purposes.

  • Consumer ISM Equipment (18.107(g)). ISM equipment used or intended to be used by the general public in a residential environment, notwithstanding use in other areas. Examples are domestic microwave ovens, jewelry cleaners for home use, ultrasonic humidifiers.

  • Magnetic Resonance Equipment (18.107(j)). ISM equipment in which RF energy is used to create images and data representing spatially resolved density of transient atomic resources within an object.

Definition of ISM frequency in the United Sates (different to Asia or Europe): A frequency (band) which is assigned by 47 CFR Part 18.301 for the use of ISM equipment. The following frequency bands are allocated for use by ISM equipment in the US:

ISM frequency bands table for USA


The conducted emission limits for FCC Part 18 consumer devices (public AC mains port connection 47 CFR 18.307) are identical to the Class B CISPR 32 limits, see commission amending of FCC in 2002:

However, there are special limits for:

  • Induction cooking ranges and ultrasonic equipment (graphic below)

  • RF lighting devices. The lighting device's maximum RF emissions are defined in [uV] by the FCC (table below).

FCC part 18 conducted emission limits
FCC part 18 conducted emission limits RF lighting devices table

The radiated emission limits of FCC Part 18:

  • According to 47 CFR 18.305(a), ISM equipment operating on a US ISM frequency is permitted unlimited radiated energy in the band specified for that frequency.

  • The field strength levels of emissions outside the ISM bands (47 CFR 18.301), shall not exceed the values specified in the tables below (unless otherwise indicated in 47 CFR 18.305):

FCC part 18 radiated emission limits
FCC part 18 radiated emission limits RF lighting

5.9  FCC vs. CISPR

The EMC standards by the international and European committees IEC/CISPR (first meeting in 1933, evolving up to today) and the EMC regulations by the United States's FCC (first emission limits set in 1979) have been shaping the landscape of EMC testing on a global scale. Many countries and customs unions are adopting the EMC standards and regulations from IEC/CISPR and FCC. This is why the focus of this website lays primarily on IEC/CISPR and FCC standards and regulations. 

The major differences between FCC regulations and IEC/CISPR standards are:

  • Rules vs. Standards. The FCC publishes legally binding rules and regulations (47 CFR), which contain concrete emission limits or in the case of FCC MP-5-1986 even test methods for FCC Part 18 (ISM equipment). On the other side, IEC and CISPR publish EMC standards. These standards are by their nature not legally binding. They can become legally binding if a country or customs union (e.g. EU) decides to:

    • Adopt these standards into national (legally binding) standards.

    • Refer to these standards from their law (regulations, directives). This is e.g. the case for the EU, where the EU publishes via its Official Journal, which EMC standards are to apply so that a product gets the presumption of conformity status.

  • Immunity. As of today [2022], the FCC regulations do not specify a level of electromagnetic immunity/susceptibility. However, there are plenty of IEC immunity standards defined.

  • Conducted Emission - FCC Part 15 / unintentional radiators. The conducted emission limits for FCC Part 15 (public AC mains port connection, 47 CFR 15.107) are identical to the CISPR 32 limits (commission amending of FCC in 2002).

  • Radiated Emission - FCC Part 15 / unintentional radiators. The FCC released a document that describes the applicability of CISPR standards for FCC 15 subpart B (unintentional radiators) approval.

The graphs below show the comparison of the FCC Part 15 vs. CISPR 22 / CISPR 32 limits for unintentional radiators in the frequency range from 30MHz up to 6GHz.

FCC 15 vs. CISPR 22 / 32. 30-1000MHz. 10m.
FCC 15 vs. CISPR 22 / 32. 30-1000MHz. 3m.
FCC 15 vs. CISPR 22 / 32. Above 1GHz (1GHz-6GHz, 1GHz-40GHz). 3m.
6 Immunity

6  EMC Immunity Standards

In the next chapters, we summarized some widely applied EMC immunity standards:

Performance Criteria.
When it comes to immunity (susceptibility) EMC testing, the term performance criteria is important to understand. Performance criteria are used for the evaluation of the immunity characteristics of equipment in the course of an EMC immunity test. The pass/fail criteria (which are specified prior testing in the test plan) for an immunity test of an EUT are set to either criterion A, B or C.
  • Criterion A. The equipment should continue to operate as intended during and after the test. No degradation of performance or loss of function is allowed below a performance level specified by the manufacturer, when the equipment is used as intended. The performance level may be replaced by a permissible loss of performance. If the minimum performance level or the permissible performance loss is not specified by the manufacturer, either of these may be derived from the product description and documentation and what the user can reasonably expect from the equipment if used as intended.
  • Criterion B. The equipment should continue to operate as intended after the test. No degradation of performance or loss of function is allowed below a performance level specified by the manufacturer, when the equipment is used as intended. The performance level may be replaced by a permissible loss of performance. During the test, degradation of performance is however allowed. No change of actual operating state or stored data is allowed. If the minimum performance level or the permissible performance loss is not specified by the manufacturer, either of these may be derived from the product description and documentation and what the user may reasonably expect from the equipment if used as intended.
  • Criterion C. Temporary loss of function is allowed, provided the function is self-recoverable or can be restored by the operation of the controls.
Test level selection - Electromagnetic environmental classes.
The EMC immunity standards define different immunity test levels (e.g. 1, 2, 3, 4, X). The EMC product (family) standards or the generic EMC standards define which immunity test level must be applied, depending on the electromagnetic environment. The immunity test levels should be selected in accordance with the most realistic installation and environmental conditions. ​In the chapters below, you can find lists of the electromagnetic environmental classes of the different IEC immunity standards (IEC 61000-4-x).

6.1  IEC 61000-4-2

The IEC/EN 61000-4-2 EMC standard is about immunity testing (measurement techniques) against electrostatic discharge (ESD). This standard is part of the Basic EMC Publications.

IEC 61000-4-2 specifies immunity to electrostatic discharge (ESD) from operating personnel and from neighboring objects. The standard defines requirements, test methods and test levels. The purpose of IEC 61000-4-2 is to establish a general and reproducible basis for the determination of the performance of electrical and/or electronic equipment when exposed to ESD. It also includes discharges of static electricity from persons to objects near the equipment under test.

Test Setup.

There are two test methods defined, whereas the first one is the most commonly applied and the only accepted method of demonstrating conformance:

  1. Type conformity test performed in the laboratories.

  2. Test at the place of installation of the EUT.

The test setup described in the following refers to the type of conformity test performed in the laboratory. The following environmental conditions must be met during the ESD test:

  • Temperature: 15°C to 35°C

  • Relative humidity: 30% to 60%

  • Atmospheric pressure: 86kPa (860mBar) to 106kPa (1060mBar)


The test setup comprises the ESD test generator (ESD gun/simulator), the equipment under test (EUT) and its auxiliary equipment (AE) necessary to perform direct and indirect application of discharges to the EUT as applicable, in the following manner:

  • Contact discharge to conductive surfaces of the EUT and to a neighboring coupling plane of the EUT (horizontal coupling plane HCP, vertical coupling plane VCP).

  • Air discharge to insulating surfaces of the EUT.

Typical test setups for table-top devices and floor-mounted apparatuses (with earth connection) are shown below.

ESD test setup
ESD test setup floor mount apparatus

The ESD generator emulates an electrical discharge of the human body. The storage capacity chosen for the ESD generator is a capacity of 150pF which is representative of that of the human body. A resistance of 330Ω was selected, which represents the source resistance of the human body when holding a metallic object in the hand (such as a key or a tool). A simplified circuit of an ESD gun (ESD generator) is drawn below. The discharge switch is switching while executing the contact-discharge testing and it is permanently closed during air-discharge testing.

ESD gun simulator circuit diagram

In order to allow a comparison of the test results of different test generators, the characteristics (values) given in the table below must be proved, whereby the return line, which is also used in the test, is used for the discharge circuit.

ESD test current waveform parameters
ESD test gun discharge current

Test Levels.

Electrostatic discharges are applied to the EUT at points and surfaces which are normally accessible to the operator under normal operating conditions. These discharges are also applied to the metal coupling planes (HCP, VCP). The voltage levels are increased gradually until the maximum severity level selected is reached. Discharges to the EUT and coupling plane are performed at a minimum of 1sec intervals at each polarity.

IEC61000-4-2 test levels voltage kV

The following table below should help to determine which test level to apply for specific relative humidity levels and materials involved (test levels are specified in the corresponding Product (Family) EMC Standard or Generic EMC Standard).

How to choose ESD test level

6.2  IEC 61000-4-3

The IEC/EN 61000-4-3 EMC standard is about immunity testing (measurement techniques) against radiated, radio-frequency electromagnetic fields. This standard is part of the Basic EMC Publications.

The object of IEC 61000-4-3 is to establish a common reference for evaluating the immunity of electrical and electronic equipment when subjected to radiated, radio-frequency electromagnetic fields. The test method documented in this part of IEC 61000 describes a consistent method to assess the immunity of an equipment or system against a defined phenomenon. This part deals with immunity tests related to the protection against RF electromagnetic fields from any source. Particular considerations are devoted to the protection against radio-frequency emissions from digital radiotelephones and other RF emitting devices.

Test Setup.

Tests have to be conducted in a shielded anechoic chamber (due to the high field strength). The distance between the RF generation antenna and the equipment under test (EUT) is typically 3m. Testing should be performed in a configuration that is as close as possible to the actual conditions in which the EUT will be used. A metallic grounding plane is not required, but the EUT should be placed on a table or support made of a non-metallic, non-conductive material (0.8m table height for table-top equipment, 0.05m to 0.15m support height for floor-standing equipment). Low dielectric constant materials such as polystyrene are recommended for non-conducting tables and supports. Materials like wood can become reflective when exposed to higher frequencies.

The manufacturer's wiring and connectors should be used for the tests. If the required wiring length required for the EUT is less than 3m, then the specified length should be used. If the required length is longer, a minimum of 1m of cable should be exposed to the RF field, and excess cables should be bundled in the center of the cable in lengths of 30-40cm.

IEC 61000-4-3 test setup (distance)

Here is the list of the most important test equipment needed:

  • Anechoic Chamber. The dimensions of the anechoic chamber must be sufficient to produce a homogeneous field of sufficient size with respect to the EUT. Additional absorbers can be used to reduce reflections in chambers that are not fully lined.

  • EMI Filters. Though not always necessary, the use of filters should not add any additional resonance effects during the test.

  • RF Signal Generator. The RF signal generator must be able to generate in the frequency band of interest an amplitude modulated signal (1kHz sine wave with 80% modulation depth). 

  • Power Amplifier. The power amplifier enables the antenna to emit the required field strength. Distortion: Harmonics must be at least 6dB below the fundamental frequency. A linearity check must be performed before testing to ensure that the RF amplifier used is not operating in compression

  • Field Generating Antenna. These can be either bi-conical, log-periodic, horn or any other linearly polarized antenna system that fulfills the frequency requirements.

  • Isotropic Field Sensor. The sensor must have adequate immunity to the field strength being measured. Usage of a fiber optic link to an indicator outside the chamber is recommended.

  • Equipment to Record Power Levels. This equipment is for logging the necessary power levels for the generation of the required field strength.

Test Levels.

IEC 61000-4-3 does not suggest that a single test level is applicable over the entire frequency range. Rather, it should be tested for the appropriate test level for each frequency range.

Testing for general purpose RF immunity covers the 80MHz to 1000MHz frequency range and should be performed without any gaps.

For mobile communication and other higher frequency devices, tests should be performed in the 800MHz to 960MHz and 1.4GHz to 6.0GHz frequency ranges. Tests in these ranges do not need to be applied continuously over the entire range, and the ranges may be limited to specific frequencies for compliance with specific operating bands in the country the product will be sold in.

IEC 61000-4-3 test levels


The specific product standards establish the most appropriate level for each frequency range. The test levels and the frequency bands are selected in accordance with the electromagnetic radiation environment to which the EUT can be exposed when finally installed. The electromagnetic environment for radiated immunity according to IEC 61000-4-3 is divided into the following classes:

  • Class 1.  Low-level electromagnetic radiation environment. Levels typical of local radio/television stations located at more than 1 km, and transmitters/receivers of low power.

  • Class 2. Moderate electromagnetic radiation environment. Low power portable transceivers (typically less than 1W rating) are in use, but with restrictions on use in close proximity to the equipment. A typical commercial environment.

  • Class 3. Severe electromagnetic radiation environment. Portable transceivers (2W rating or more) are in use relatively close to the equipment but not less than 1m. High power broadcast transmitters are in close proximity to the equipment and ISM equipment may be located close by. A typical industrial environment.

  • Class 4. Portable transceivers are in use within less than 1m of the equipment. Other sources of significant interference may be within 1m of the equipment.

  • Class X: X is an open level which might be negotiated and specified in the product standard or equipment specification.


6.3  IEC 61000-4-4

The IEC/EN 61000-4-4 EMC standard is about immunity testing (measurement techniques) against repetitive electrical fast transients (EFT), also called bursts. This standard is part of the Basic EMC Publications.

IEC 61000-4-4 defines immunity requirements, test setups, test procedures, test equipment (and their calibration and verification) and ranges of test levels related to repetitive electrical fast transients (EFTs, bursts). In reality, bursts originate from switching transients: interruption of inductive loads, relay contact bounce, etc. 

The object of IEC 61000-4-4 is to establish a common and reproducible reference in order to evaluate the immunity when subjected to bursts on the following ports:

  • Supply ports

  • IO (signal, control) ports (if cable length >3m)

  • Earth ports

Test Setup.

Floor standing EUTs and equipment designed to be mounted in other configurations, unless otherwise mentioned, shall be placed on a ground reference plane and shall be insulated from it by an insulating support with a thickness of 0.1m ±0.05m including non-conductive castors. Table-top equipment and equipment normally mounted on ceilings or walls as well as built-in equipment shall be tested with the EUT located 0.1m ±0.01m above the ground reference plane. The following picture shows locations for supply line coupling (A) and location for signal lines coupling (B).

Burst (EFT) testing setup

The simplified circuit diagram of the generator is given below. The effective output impedance of the generator shall be 50Ω. Here is the explanation of the components:

  • RC. Charging resistor

  • CC. Energy storage capacitor

  • RS. Impulse duration shaping resistor

  • Rm. Impedance matching resistor

  • Cd. DC blocking capacitor 10nF±2nF


The burst generator output signal consists of periodic burst pulse packages (75 pulses per package). The burst period is 300msec and the repetition period is either 10µsec (100kHz) or 200µsec (5kHz).

IEC 61000-4-4 burst pulses

Test Levels.