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ANSI C63 is the US Accredited Standards Committee on Electromagnetic Compatibility, operating under American National Standards Institute rules with the IEEE holding its secretariat. Unlike CISPR, which publishes emission limits, C63 concentrates on how to measure: test methods, receiver and instrumentation specifications, antenna calibration and test site validation. Its flagship document, ANSI C63.4, is the measurement procedure the FCC requires for unintentional radiator testing under 47 CFR Part 15.
What is the ANSI ASC C63 committee?
ANSI Accredited Standards Committee C63 (full name: Accredited Standards Committee C63 - Electromagnetic Compatibility) brings together test laboratories, manufacturers, regulators and instrumentation makers to write consensus EMC standards for the United States. The committee traces its roots to the 1930s work on radio noise measurement and today maintains more than a dozen active standards. Its output is referenced directly in US federal regulation: the FCC equipment authorization rules point to C63 documents as the accepted measurement procedures. Donald N. Heirman chaired the committee and, earlier, the working group that maintained C63.4; his standards career is covered in the biography.
Which standards does ANSI C63 publish?
The key documents fall into three groups: instrumentation specifications, measurement methods and application-specific procedures.
| Standard | Title / scope | Typical use |
|---|---|---|
| ANSI C63.2 | Specifications for electromagnetic noise and field strength instrumentation, 9 kHz to 40 GHz | Defines EMI receiver and detector performance (quasi-peak, peak, average) |
| ANSI C63.4 | Methods of measurement of radio-noise emissions from low-voltage electrical and electronic equipment, 9 kHz to 40 GHz | Radiated and conducted emission testing of unintentional radiators for FCC Part 15 Subpart B |
| ANSI C63.5 | Radiated emission measurements - antenna calibration | Antenna factor determination and normalized site attenuation reference data |
| ANSI C63.10 | Testing unlicensed wireless devices | Compliance measurements of intentional radiators (Wi-Fi, Bluetooth, remote controls) under FCC Part 15 Subpart C |
| ANSI C63.15 | Immunity measurement methods and instrumentation | Voluntary immunity evaluation of US products (the FCC does not mandate immunity) |
| ANSI C63.19 | Hearing aid compatibility with wireless communications devices | Measuring RF interference and coupling between mobile phones and hearing aids |
| ANSI C63.26 | Compliance testing of transmitters used in licensed radio services | Measurement procedures for licensed transmitters (cellular, land mobile, microwave) |
Each standard is revised on a multi-year cycle; always confirm the edition referenced by the current FCC rules or by your accreditation scope before testing.
How does ANSI C63.4 relate to FCC testing?
ANSI C63.4 is the how, FCC Part 15 is the what. The FCC publishes the legal emission limits in 47 CFR Sections 15.107 (conducted) and 15.109 (radiated), and Section 15.31 designates ANSI C63.4 as the measurement procedure for unintentional radiators. In practice this means a test laboratory measuring a laptop, monitor or LED driver for the US market sets up the equipment, arranges cables, selects detectors and validates its test site according to C63.4, then compares results against the limits described on our FCC Part 15 page. The current base edition is ANSI C63.4-2014; the FCC’s Office of Engineering and Technology publishes guidance (KDB documents) on which editions and amendments are accepted at any given time.
Where does C63 fit among the other EMC families?
C63 methods and CISPR methods address the same physics and have converged over decades of coordination, much of it driven by people like Don Heirman who held leadership roles in both bodies. Differences remain in details such as measurement distances and site validation criteria, so a lab serving both US and EU markets typically maintains competence in both. For the international emission standards see the CISPR page; for immunity methods, which C63.15 covers only voluntarily in the US, see IEC 61000. Practical measurement concepts used throughout C63 documents - LISN, quasi-peak detector, normalized site attenuation - are defined in the EMC glossary and explained in EMC testing basics.