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What does FCC Part 15 require?

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47 CFR Part 15 governs US radio-frequency devices that operate without an individual license. It covers unintentional radiators (digital devices, Subpart B), intentional radiators such as Wi-Fi, Bluetooth and remote controls (Subpart C), and other subparts for U-NII and other devices. Part 15 devices must not cause harmful interference and must accept interference received.[1]

What are the Class A and Class B limits?

Section 15.109 sets radiated limits for unintentional radiators. Class B (residential), measured at 3 m: 100 µV/m (30–88 MHz), 150 µV/m (88–216 MHz), 200 µV/m (216–960 MHz), 500 µV/m (above 960 MHz). Class A (commercial/industrial), at 10 m: 90, 150, 210 and 300 µV/m in the same bands. Conducted limits on AC mains (15.107) apply from 150 kHz to 30 MHz.[1]

What rules apply in the 2.4 GHz band?

Section 15.247 permits frequency-hopping and digitally modulated systems in 902–928 MHz, 2400–2483.5 MHz and 5725–5850 MHz with up to 1 W conducted output (with lower limits for some hopping systems) and antenna gain up to 6 dBi before power reduction is required, with special provisions for fixed point-to-point links. Section 15.249 covers low-power transmitters with field-strength limits. U-NII devices fall under Subpart E.[1]

How is equipment authorized?

Intentional radiators generally require certification by a Telecommunication Certification Body based on accredited lab testing; many unintentional radiators can use the Supplier’s Declaration of Conformity (SDoC). Authorization procedures are in 47 CFR Part 2.[2]

Frequently asked questions

Does Part 15 apply to hobby projects?

Yes; Part 15 limits apply to any device operated in the US, though there are provisions for limited home-built devices.

What is a Part 15 'harmful interference' condition?

Operators must stop operation if it causes harmful interference to licensed services.

Are 5 GHz Wi-Fi rules in Part 15?

Yes, under Subpart E (U-NII) and 15.247 for 5725–5850 MHz.

References

Online sources accessed October 21, 2026; printed works cited by edition. See all sources.

  1. “47 CFR Part 15: Radio Frequency Devices”. U.S. Federal Communications Commission, via eCFR. current.
  2. “47 CFR Part 2: Frequency Allocations and Radio Treaty Matters; General Rules and Regulations”. U.S. Federal Communications Commission, via eCFR. current.
Categories: EMC and EMI