FCC Part 15 Subpart B testing for unintentional radiators

FCC Part 15 Subpart B — Unintentional Radiator Testing

FCC Part 15 Subpart B regulates unintentional radiators — digital devices that generate radio frequency energy as a byproduct of their operation but are not designed to transmit. Compatible Electronics provides comprehensive Class A and Class B emissions testing per ANSI C63.4 (2014), the accredited measurement standard referenced by the FCC for Part 15B compliance.

NVLAP Accredited FCC Listed Lab ISO/IEC 17025:2017 Class A & Class B

What are Unintentional Radiators?

Unintentional radiators are devices that generate RF energy during normal operation but whose primary purpose is not radio communication. This includes computers, monitors, printers, power supplies, LED drivers, motor controllers, and virtually all digital electronic equipment. Any device with a digital clock or switching circuit operating above 9 kHz falls under Part 15B jurisdiction and requires compliance before being marketed in the United States.

Class A vs. Class B Devices

Class A

Commercial / Industrial Use

Marketed for use in commercial, industrial, or business environments
Less stringent limits reflecting lower risk of residential interference
Enterprise networking equipment, industrial controllers, data center equipment

Class B

Residential Use

Marketed for use in residential environments
Approximately 10 dB more stringent than Class A to protect home radio and TV reception
Consumer products sold to the general public require Class B compliance

Classification Rules

Product marketing and intended use environment — not the design — determines classification
Peripheral devices default to Class B unless marketed exclusively for commercial use
External switching power supplies: Class B limits apply for residential-market supplies

Radiated Emissions Testing

Measurement Parameters

Frequency range: 30 MHz to 1 GHz standard
Extended above 1 GHz for devices with clock frequencies above 108 MHz
3-meter and 10-meter measurement distances in accredited test facilities
Antenna height scan 1–4 meters; horizontal and vertical polarization
Quasi-peak and average detector measurements
Equipment under test operated in all representative configurations

Conducted Emissions Testing

Frequency range: 150 kHz to 30 MHz
AC power line measurements using 50 µH/50 Ω LISN
Both line and neutral conductors measured
Quasi-peak and average detector limits
DC power port conducted emissions where applicable

Standards We Test To

USA

ANSI C63.4 (2014)

Methods of Measurement of Radio-Noise Emissions from Low-Voltage Electrical and Electronic Equipment (9 kHz to 40 GHz). Primary FCC Part 15B measurement standard.

Accredited at Lake Forest/Silverado, Brea, and Newbury Park

Canada

ICES-003 Issue 6 & Issue 7

Industry Canada Information Technology Equipment standard — equivalent to FCC Part 15B for the Canadian market.

ICES-003 Issue 6 (2016) — Accredited at Lake Forest/Silverado and Brea
ICES-003 Issue 7 (October 2020) — Accredited at all three locations

EN 55032 (2015)+A11(2020)

Electromagnetic compatibility of multimedia equipment — emission requirements for the EU market equivalent.

Accredited at all three locations

Products We Test

Computing & Peripherals

Computers, laptops, tablets, and servers
Monitors, displays, and televisions
Printers, scanners, and computer peripherals
Networking equipment (routers, switches, access points)

Power & Lighting

External switching power supplies and AC adapters
LED lighting systems and drivers

Industrial & Connected

Industrial controllers and programmable logic controllers (PLCs)
Consumer electronics and smart home hubs
IoT gateways and connected devices with digital processing
Medical device enclosures with embedded digital circuits

Real-World Testing Examples

Commercial Network Switch — Class A

A networking equipment manufacturer needed FCC Part 15B compliance for a 48-port managed Ethernet switch marketed to enterprise data centers. Compatible Electronics performed radiated emissions per ANSI C63.4 (2014) from 30 MHz to 1 GHz and conducted emissions on the AC mains from 150 kHz to 30 MHz. All switching frequencies and harmonics were captured across multiple operating modes including full traffic load. The accredited test report supported the SDoC filed with the FCC for commercial distribution.

IoT Gateway — Part 15B + ICES-003 Combined

An industrial IoT company required both FCC Part 15B and Industry Canada ICES-003 compliance for a factory automation gateway with a multicore ARM processor and switching power supply. Compatible Electronics performed ANSI C63.4 testing for the FCC SDoC and ICES-003 Issue 7 testing for Canadian compliance in a single measurement session. A combined test report covering both markets eliminated the need for a separate Canadian test session.

LED Driver — Residential Class B

A consumer lighting manufacturer required Class B Part 15B compliance for a dimmable LED driver used in residential fixtures sold through retail channels. Compatible Electronics performed radiated and conducted emissions per ANSI C63.4 across dim levels from 10% to 100%, identifying a conducted emission issue at the third harmonic of the switching frequency that was resolved through a filter modification before final certification testing.

Authorization and Compliance

Supplier's Declaration of Conformity (SDoC) required — no FCC ID needed for unintentional radiators
FCC compliance statement required on device label or in user manual
Unique identifier required for each product model
Test records must be retained and made available to the FCC upon request
ICES-003 compliance statement and labeling required for Canadian market