EMC regulation in the United States: FCC Part 15 and Part 18
FCC rules for unintentional and intentional radiators, Class A and Class B limits, measurement standards, equipment authorization and what the FCC does not regulate.
In the United States the Federal Communications Commission (FCC) regulates radio-frequency emissions from electronic products under Title 47 of the Code of Federal Regulations.
What the rules cover
- Part 15 covers radio-frequency devices. Subpart B applies to unintentional radiators (digital devices, computers, many consumer electronics); Subpart C and following subparts apply to intentional radiators (devices that transmit by design, such as Wi-Fi, Bluetooth or remote controls).
- Part 18 covers industrial, scientific and medical (ISM) equipment that generates RF energy (for example induction heaters, microwave ovens and some medical equipment), with its own limits and procedures.
- The rules regulate emissions: conducted emissions (150 kHz to 30 MHz, section 15.107) and radiated emissions above 30 MHz (section 15.109). The range of frequencies to be measured for radiated emissions depends on the highest frequency used in the device (section 15.33).
- There is no general FCC immunity requirement. Immunity is addressed by other regulators (for example for medical devices), by customer requirements or by industry standards.
Class A and Class B
Limits are split into Class A (digital devices marketed for use in commercial, industrial or business environments) and Class B (devices marketed for residential use; these limits are stricter). The user manual or label must carry the statement the rules require for the class (section 15.105).
Measurement methods
The FCC incorporates by reference ANSI C63.4 for unintentional radiators and ANSI C63.10 for intentional radiators; the rules list which edition applies (section 15.31). Test sites and laboratories are specified in the rules and the Commission’s guidance.
Equipment authorization
Part 2 sets the authorization procedures:
- Most unintentional radiators (Part 15 Subpart B digital devices) use the Supplier’s Declaration of Conformity (SDoC): the responsible party gets the product tested, keeps the records and includes the required compliance statement; the responsible party for an SDoC must be located in the United States.
- Intentional radiators generally require certification, issued by an FCC-recognised Telecommunication Certification Body (TCB) after testing.
- Specific rules, exemptions and labelling requirements apply by device type.
Check Part 2 and the FCC’s equipment-authorization pages for the route that applies to a specific device.
Other US sectors
- Medical devices: the FDA recognises standards such as IEC 60601-1-2, and addresses EMC in its premarket review.
- MIL-STD and aerospace: MIL-STD-461 and RTCA DO-160 are contract or certification requirements (see Aerospace and MIL-STD EMC).
- Automotive: there is no federal EMC type-approval scheme comparable to UN Regulation No. 10; OEM specifications dominate.
Where to check
The current text of the rules is on eCFR; the FCC publishes guidance on equipment authorization.
Sources
- 47 CFR Part 15, Radio frequency devices (eCFR)
- 47 CFR 15.101, equipment authorization of unintentional radiators
- 47 CFR 15.105, information to the user (Class A and Class B)
- 47 CFR 15.107, conducted limits
- 47 CFR 15.109, radiated emission limits
- 47 CFR 15.31, measurement standards
- 47 CFR Part 2, general rules including equipment authorization
- 47 CFR Part 18, industrial, scientific and medical equipment