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The ANSI-Accredited Standards Committee on EMC – C63®

Many EMC engineers consider the American National Standards Institute (ANSI) C63® Committee on EMC (the Main Committee) to be the National Committee on EMC for the United States. The Main Committee develops standards in the sector of electrical engineering called electromagnetic compatibility (EMC) engineering. The current committee makeup is 30 organizations and nine independent consultants; the Main Committee meets twice a year in various locations around the continental U.S. This article discusses some of the latest standards developed by (or under development by) the Committee.

The Committee’s Operation

The Main Committee is organized in a top-down fashion, although the standards development is actually done by the lowest-level (working group) and then approved by higher levels of the Committee’s organization. The highest level is the Main Committee, currently Chaired by Dan Hoolihan.
The Vice-Chair is Dan Sigouin, the Treasurer is
Mike Windler and the Secretary is Jerry Ramie.

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The Main Committee is supported by eight subcommittees. The subcommittees (with their respective chair-persons) are: shown in Table 1.


SC1 – EMC Techniques and Development Zhong Chen
SC2 – E3 Terminology Definitions and Best Practices Chris Dilay
SC3 – International Standardization Donald Heirman
SC4 – Wireless and ISM Equipment Measurements Bob DeLisi
SC5 – Immunity Testing and Measurements Ed Hare
SC6 – Laboratory Accreditation Randy Long
SC7 – Wireless Coexistence Vladimir Bazhanov
SC8 – Medical Device EMC Test Methods Stephen Berger

Table 1


Each subcommittee has several working groups reporting to it and each working group has responsibility for one standard. The standards that are developed are considered to be American National Standards. They imply a consensus of those parties concerned with its scope and provisions. An American National Standard is intended as a guide to aid the manufacturer, the consumer, and the general public.

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The procedures of ANSI require that action be taken to reaffirm, revise or withdraw standards
no later than five years from their date of publication. Our Main Committee’s goal is also to develop new standards as appropriate. In 2017 and 2018 we have published two revised standards (C63.5, C63.15), published one new standard (C63.27), and amended one of our long-time standards (C63.4).

C63.15 – 2017

American National Standard Recommended Practice for the Immunity Measurement of Electrical and Electronic Equipment

This revised standard, approved 13 July 2017 and published 1 March 2018, supersedes the last version of the standard dated 2010. Major additions to and modifications of the 2010 version of the standard include:

  • Automotive immunity testing – both conducted and radiated phenomena
  • Immunity to nearby radio-frequency (RF) wireless communications equipment (proximity fields)
  • Quasi-static immunity testing
  • More complete specification of the contents of the evaluation (test) report
  • An Annex C identifying applicable information sources by standard, clause, figure, and table.

In the Overview of the standard, it states:

“This recommended practice is intended to: (1) Identify preferred or optional immunity test methods, (2) Describe specific measurement techniques, (3) Suggest product performance criteria as applicable to general and specific products, and (4) Identify test instrumentation specifications.”

(Note – The Main Committee utilizes the Institute of Electrical and Electronic Engineers (IEEE) – Standards Association to publish its standards and they are dual-coded to indicate the standards also meet IEEE criteria; that is, they are ANSI/IEEE standards.)

C63.4a – 2017 – Amendment 1

Test Site Validation – 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

This was the first Amendment to a C63 standard in the 80 plus year-history of the Main Committee. The Abstract of the standard states:

“United States consensus standard methods are specified in Annex D of this amendment for validating standard test sites and alternative test sites used for measurement of radiated radio-frequency (RF) signals and noise emitted from electrical and electronic devices in the frequency range of 30 MHz to 1 GHz. In addition, various updates are made to equations in 4.5, Annex F, Annex G, and Annex N.”

Also, a change to the value of the distance between the receiving antenna and the equipment-under-test was made which returned it to what it was in previous editions of C63.4.

The more significant updates to Annex D consisted of the following:

  • Corrected the equation for calculating the measured NSA value – Equation D.1 of ANSI C63.4 – 2014;
  • Added text to clarify the single-position NSA geometry for validation of standard test sites;
  • Added requirements for maximum frequency step-size for both the discrete frequency method and the swept frequency method, also quantified the existing requirement for the receive antenna height scan rate for the swept-frequency method;
  • For the swept frequency method, added the requirement to report in tabular format those measured NSA values that are within the 1 dB of the site acceptability criterion;
  • Removed the provision from D.3 for moving the antenna inward from the periphery for the left and right positions in horizontal polarization;
  • Added equations to be used for calculating theoretical NSA for an ideal site, which can be used for frequencies and/or geometries other than those listed in the tables;
  • Expanded the tables of theoretical NSA for an ideal site by adding values for a five-meter horizontal-distance measurement, for greater transmit antenna heights taller than two-meters, and for the frequency increments specified in the measurement procedure sub-clauses; and
  • Updated the figures and added a top-view figure for vertical polarization depicting the re-orientations of the transmit antenna and the receive antenna for the left and right positions of the transmit antenna.

(Note – The measurement distance criterion for electric field strength measurements (1 GHz to 40 GHz) with horn antennas in 4.5.5 (and in table footnotes in 4.5.1) of ANSI C63.4-2014 is modified to as it was in the 1992 edition of ANSI C63.4 and consistent with CISPR 16-1-4 ad CISPR 16-2-3.)

C63.5 – 2017

American National Standard for Electromagnetic Compatibility – Radiated Emission Measurements in Electromagnetic Interference (EMI) Control – Calibration and Qualification of Antennas (9 kHz to 40 GHz)

C63.5 was published in May of 2017 and it is a revised version of the C63.5-2006 standard.

Its Abstract says:

“Abstract: Methods for determining antenna factors of antennas used for radiated emission measurements in electromagnetic interference (EMI) control from 9 kHz to 40 GHz are provided. Antennas included are linearly polarized antennas such as loops, rods (monopoles), tuned dipoles, biconical dipoles, log-periodic dipole arrays, biconical and log-periodic dipole array hybrids, broadband horns, etc., that are used in measurements prescribed by ANSI C63.4 and ANSI C63.10. The antenna calibration methods include standard site method (i.e., the three-antenna method), reference antenna method, equivalent capacitance substitution method, standard transmit-loop method, standard antenna method, and standard field method.”

Changes from the previous edition include several text corrections, a new sub-clause to provide free-space correction terms for tuned dipole antennas, and another new sub-clause for requirements of frequency spacing. These were added along with a sub-clause and an annex on the use of time-gating to determine free space antenna factors (FSAFs) above 1 GHz.

Other items that were changed are additional details for horn antenna calibration requirements, addition of an equation and associated details for “vertical max Ed” in Annex A, clarifications/updates to the symmetry measurement for antennas used from 30 MHz to 300 MHz, an expansion of allowable reference antennas, and expanded information about estimating measurement uncertainties.

Furthermore, selected portions of IEEE STD 291™-1991 for loop antenna calibration measurements are provided in a new annex, antenna calibration site (ACS) requirements were expanded and placed in a separate annex, and an annex was added for measurement uncertainty of the reference antenna method (RAM).

The standard provides procedures for the determination of antenna factors (AFs) for antennas used in radiated emission measurements as described in ASC C63® measurement documents. It is important to note that these AFs shall be used for either vertically polarized or horizontally polarized measurements at distances from the EUT of 3-meters or more. The general measurement conditions and parameters for antenna calibration and characterization are covered in the main body of the standard.

Table 1 in the standard gives a summary of antenna types and the calibration methods used for product measurement and normalized site attenuation (NSA) measurement purposes.

(Note – The three most commonly used antenna calibration methods are detailed in the standard:

  • Standard site method (SSM)
  • Reference antenna method (RAM)
  • Equivalent capacitance substitution method (ECSM)

Free-space antenna factors (FSAFs) and near-free-space antenna factors (NFSAFs) are examined in the standard.)

ANSI/IEEE C63.27 (C63.27) – 2017

American National Standard for Evaluation of Wireless Coexistence

C63.27 was published in May of 2017 and is a new standard for the C63-Committee. Its Abstract says:

“Abstract: An evaluation process and supporting test methods are provided in this standard to quantify the ability of a wireless device to coexist with other wireless services in its intended radio-frequency (RF) environments.”

The Introduction of the standard states:

“The proliferation of radio-frequency (RF) wireless devices has been both explosive and pervasive in virtually every field in our society. The everyday use of wireless devices goes well beyond the early handheld walkie-talkies, introduced in the 1950s.

“It is estimated that cellular telephones outnumber individuals in the US population and other countries have even higher penetration rates for cell (mobile) phone usage.

Wireless technologies have resulted in the birth of new applications like radio-frequency identification (RFID) systems and distributed sensor systems. Thousands of types of equipment used in consumer and industrial environments now contain one or more wireless technologies. Almost every building now contains a wireless network to support multiple uses of wireless devices. While the benefits of wireless technology are obvious and explain the explosive growth in both number and applications of wireless technology, there are also risks and disadvantages.

“These risks must be carefully evaluated and managed. As wireless technology is integrated into systems that require high degrees of reliability, such as medical devices, aircraft, and nuclear power plants, it is imperative that risks be quantified, mitigated, and managed to be at or below acceptable levels. Verification of the risk control measures associated with the following two areas are of interest to this group: 1) traditional EMC and 2) coexistence.

“Traditional EMC testing is designed to exclude frequency bands where the device under test communicates wirelessly. Coexistence testing focuses on devices and systems that intentionally use wireless and it extends beyond traditional EMC to examine the device’s performance in frequency bands where it uses wireless communication. This standard provides methods for evaluating the ability of a device to coexist in its intended RF wireless communications environment.”

The subject standard specifies methods for assessing the radio frequency (RF) wireless coexistence of equipment that incorporates RF communications. It specifies key performance indicators (KPIs) that can be used to assess the ability of the equipment under test (EUT) to coexist with other equipment in its intended operational environment.

“Co-existence” has a complex definition in the standard:

“coexistence: (A) The ability of two or more spectrum-dependent devices or networks to operate without harmful interference. (IEEE STD 1900.1-2008 [B28]) See also: interference. (B) The ability of one system to perform a task in a given shared environment where other systems have an ability to perform their tasks and may or may not be using the same set of rules. (IEEE STD 802.15.3-2016 [B29]) (C) A state of acceptable co-channel and/or adjacent channel operation of two or more radio systems (possibly using different wireless access technologies) within the same geographical area. (IEEE STD 802.16-2012 [B30]) (D) A situation in which one radio system operates in an environment where another radio system having potentially different characteristics [e.g., radio access technology (RAT)] may be using the same or different channels, and both radio systems are able to operate with some tolerable impact to each other. (ETSI EN 303 145 V1.2.1 [B17]) Syn: RF coexistence; wireless coexistence.”

A closely-linked document has been published by the American Association of Medical Instrumentation (AAMI); it is AAMI-TIR 69:2017 Risk Management of Radio-Frequency Wireless Coexistence for Medical Devices and Systems. The ANSI document is the “test methods” standard while the AAMI standard is the “risk-assessment” aspect of the coexistence challenge.

A more detailed technical analysis of the “coexistence” subject can be found in “Characterizing the 2.4 GHz Spectrum in a Hospital Environment: Modeling and Applicability to Coexistence Testing of Medical Devices” by Mohamad Omar Al Kalaa, Walid Balid, Hazem H. Refai, Nickolas J. LaSorte, Seth J. Seidman, Howard I. Bassen, Jeffrey L. Silberberg, and Donald Witters from the IEEE Transactions on EMC.

New C63-Standards Under Development

C63.25.1 – DRAFT Standard for Validation Methods for Radiated Emission Test Sites, 1 -18 GHz

This draft standard describes a time domain site voltage standing wave ratio (SVSWR) test method for qualifying sites from 1 to 18 GHz. This method is intended to be used in place of the present SVSWR test method being utilized in the international world. As test sites are developed or improved to be used above 18 GHz, the time domain SVSWR test method will become increasingly important.

C63.28 – DRAFT Guide for Best Practices for Electromagnetic Compatibility

The Working Group working on this guide is reviewing Annex B of the Engineering Practice Study published in 2001 by the Department of Defense/Industry E3 Standards Committee chaired by DISA/Joint Spectrum Center. The WG is attempting to compare Military EMC standards with more generalized versions of commercial EMC Standards to arrive at “practices” that represent the best of both the commercial and military worlds.

C63.29 – DRAFT American National Standard for Methods of Measurement of Radio-Noise Emissions from Lighting Products

The Abstract for this standard says:

“United States consensus standard methods, instrumentation, and facilities for measurement of radio-frequency (RF) signals and noise emitted from lighting equipment in the frequency range from 9 kHz to 40 GHz are specified. This standard does not include generic nor product–specific emission limits. Where possible, the specifications herein are harmonized with other national and international standards used for similar purposes.”

C63.30 – DRAFT American National Standard for Compliance Testing of Wireless Power Transfer Products

This draft standard is intended to include procedures for compliance testing of several different types of wireless power transfer (WPT) products with applicable electromagnetic compatibility (EMC) and radio-frequency (RF) regulatory requirements. Test procedures will focus on radiated field and conducted measurements and may reference established standards. WPT RF exposure compliance procedures will not be included, although standards pertaining to laboratory electromagnetic field (EMF) safety may be referenced.

WPT testing methods may consider, but are not limited to, large in-situ installations, charging systems for electric vehicles (including impact of host on electromagnetic fields), household appliances, and desktop chargers. Consideration will also be given to appropriate testing distances and test locations (such as semi-anechoic chambers, open area test sites, ground plane, and earth sites). Related national and international standards (e.g., CISPR, SAE, etc.) will be reviewed and used to the extent possible.

C63.31 – DRAFT American National Standard for Compliance Testing of Industrial, Scientific, and Medical (ISM) Equipment

This standard is intended to include procedures for compliance testing of traditional ISM with applicable radio regulatory requirements. Related national and international standards (e.g., CISPR, IEEE) will be reviewed and used to the extent possible.

It is anticipated that this standard would replace the current FCC/OET MP-5 – Methods of Measurements of Radio Noise Emissions from Industrial, Scientific and Medical equipment (February – 1986)


The ANSI-ASC C63® Committee on EMC has been in existence for approximately 80 years (we are still researching our actual start date) and has been contributing to national EMC technical issues for that period of time. Initially the Committee was focused on specifying parameters for radio-frequency receivers. Over time, the committee’s emphasis switched to testing
methods and testing environments and how to determine
and characterize both of those technical issues.

About 30 years ago, the Committee responded to a request from the FCC to develop a test methods document for Part 15 devices. The Committee responded by revising and modifying C63.4 – Methods of Measurement of Radio-Noise Emissions from Low-Voltage Electrical and Electronic Equipment in the Range of 9 kHz to 40 GHz. This document was incorporated into the FCC Rules and it replaced FCC/OET
MP-4 – FCC Procedures for Measuring RF Emissions from Computing Devices (July -1987).

A second reason for the existence of the C63 committee is to develop EMC techniques which utilize the latest electronic technology in EMC test equipment and take those new techniques to the international standards bodies for incorporation into EMC standards used world-wide. No other U.S. committee can match the technical strength, cumulative experience, and diversity of the C63 Committee. Technical members of the committee include Ph. Ds and Master degree holders and other highly educated engineers and scientists. Some members of the committee have over 50 years of experience in EMC and electrical engineering. The diversity of the committee includes industrial corporations, trade associations, testing laboratories, calibration laboratories, government bodies and individual EMC consultants.

Another reason for the existence of the C63 Committee is the unique electrical distribution system of the U.S. Most countries around the world have a 50 Hz, 380/220 volt electrical distribution system to the final user in the home or retail areas. The U.S. has a 60 Hz, 230/115 volt electrical distribution system to the final user. There are unique differences in the two systems and the C63 Committee addresses those differences in their standards while the international standards bodies do not address 60 Hz standards in many of their published works.

Finally, the U.S. needs an EMC Committee where it is the majority of the committee. In the international standards world, the U.S. gets only one vote; there is no distinction nor extra votes for a country whose gross domestic product dwarfs that of many other members of the international standards committees. In addition, the European Union controls over 25 votes because each country in the EU gets a vote at the international level. The GDP of the EU is approximately equal to the U.S.’s GDP, yet they have 25 times more voting power.

For more information on this famous U.S. EMC Committee, check out their website

Daniel D. Hoolihan is the founder and principal of Hoolihan EMC Consulting. He serves as chair of the ANSI-ASC C63 Committee on EMC. He is also a past-president of the IEEE’s EMC Society, and a current member of the Society’s Board of Directors. Hoolihan is also an assessor for the NIST NVLAP EMC and Telecom Laboratory Accreditation program. He can be reached at, or at 651-213-0966.


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