Worked example: an IoT sensor through RED and FCC

Hugues Orgitelloupdated 7 Oct 202616 min read

This is a hypothetical walkthrough: no real client, no real product, no confidential data, and no invented durations, costs or test results. The product is fictional; the rules are not. We follow an invented battery-powered environmental sensor, the "Aurora ENV-1", from its specification to a product carrying a CE marking in the European Union and an FCC authorisation in the United States. It combines a Bluetooth Low Energy radio for local configuration with a sub-GHz radio for telemetry, runs on a lithium coin cell and reports temperature and humidity. Every standard edition, article and date applied to it is read from the texts as they stand on 7 October 2026, so you can map the same sequence onto your own product.

TL;DR:

• EU. RED Articles 3(1)(a), 3(1)(b), 3(2) and 3(3)(d). Cited standards: EN 300 328 V2.2.2, EN 300 220-2 V3.3.1, EN 301 489-17 V3.3.1, EN 301 489-3 V2.3.2, EN 18031-1 with the 2025/138 restrictions. Nothing is cited under the RED for electrical safety or for the RF exposure of a wall-mounted device.
• US. Two modules with modular grants are reused within their conditions ("Contains FCC ID", 47 CFR 15.212); the digital circuitry of the sensor is a Class B digital device under SDoC or certification (15.101).
• Modules. The RED has no modular approval: module reports are evidence, the finished product is assessed and declared by its manufacturer.
• Battery. The coin cell must be readily removable by the end user from 18 February 2027 unless an Article 11(3) exception fits; the cell type, not the sensor, is UN 38.3 tested.
• Cyber. RED Article 3(3)(d) since 1 August 2025; CRA reporting since 11 September 2026; 2022/30 repealed and CRA in full from 11 December 2027.

The hypothetical product

The Aurora ENV-1 is a wall-mounted indoor sensor. Its characteristics fix the compliance scope, so the specification is the first deliverable.

Attribute	Value (hypothetical)	Why it matters for compliance
Local radio	BLE module with a modular grant, 2.4 GHz	EN 300 328 and EN 301 489-17 in the EU, 15.247 in the US
Telemetry radio	Sub-GHz module with a modular grant, one EU868 variant (868.0 to 868.6 MHz) and one US915 variant (902 to 928 MHz)	EN 300 220-2 and EN 301 489-3 in the EU, 15.247 or 15.249 in the US
Network path	Telemetry reaches a cloud service through a gateway	Makes it "internet-connected radio equipment" under 2022/30
Data processed	Temperature and humidity only; the example assumes no personal, traffic or location data	Decides whether Article 3(3)(e) also applies
Power	Non-rechargeable lithium coin cell	Battery Regulation, UN 38.3 evidence for the cell
Display	None	No FCC e-label (2.935 needs a display)
Target markets	European Union and United States	RED and 47 CFR

Two choices drive the rest. Two radios in one enclosure means simultaneous operation is part of the assessment, not each radio alone. And using modules changes what is reused: under the FCC rules a modular grant can be reused within its conditions; under the RED there is no modular grant at all. For the wider framework, see certification getting started, and for single-radio versions of the same exercise, the LoRaWAN sensor and BLE wearable guides.

Step 1: map the product to the texts

European Union

The sensor is radio equipment under 2014/53/EU, the Radio Equipment Directive (RED). Article 3(1)(a) covers health and safety, including the safety objectives of the Low Voltage Directive "with no voltage limit applying", so a 3 V coin-cell product is in scope. Article 3(1)(b) covers EMC by reference to the objectives of 2014/30/EU. The declaration therefore cites the RED, not the LVD or the EMC Directive.

RED article	Requirement	Applies to the Aurora ENV-1?	Cited standard (October 2026)	Citing decision
3(1)(a)	Health and safety, RF exposure	Yes	None for electrical safety; none for a device not used against the body (EN 50360, EN 50566, EN 50385, EN 50401 do not fit)	RED list
3(1)(b)	EMC	Yes	EN 301 489-17 V3.3.1 (BLE), EN 301 489-3 V2.3.2 (SRD); EN 301 489-1 is not cited on its own	(EU) 2025/893
3(2)	Efficient use of spectrum	Yes, both radios	EN 300 328 V2.2.2 (2.4 GHz), EN 300 220-2 V3.3.1 (868 MHz); V3.1.1 withdrawn from 11 June 2027	RED list, (EU) 2025/2499
3(3)(d)	No harm to the network	Yes: it "can communicate itself over the internet, whether it communicates directly or via any other equipment"	EN 18031-1:2024, with restrictions	(EU) 2025/138
3(3)(e)	Personal data and privacy	Only if it processes personal, traffic or location data	EN 18031-2:2024, with restrictions	(EU) 2025/138
3(3)(f)	Protection from fraud	No: it transfers no money or monetary value

For Article 3(1)(a), electrical safety is usually shown with EN 62368-1 (the edition cited under the LVD is EN 62368-1:2014 + AC:2015) and RF exposure with an assessment against Council Recommendation 1999/519/EC, for example with EN 62479 or EN 62311. None of these is in the RED list, so they appear in the file as "other technical specifications", justified, without presumption of conformity. The RED standards and RED tests pages give the full list.

The conformity assessment route follows from the table. Article 17 allows internal production control (module A) for Articles 3(1)(a) and (b) in all cases, and for Articles 3(2) and 3(3) only when the cited harmonised standards are applied in full. A notified body becomes necessary for 3(2) or 3(3) if, for example, EN 18031-1 is applied with the option letting the user "not to set and use any password" (Decision (EU) 2025/138). The RED procedure page sets out each case.

United States

The FCC rule part decides the procedure. The sensor contains two kinds of devices:

FCC scope	Rule	Procedure	Output
BLE transmitter (intentional radiator)	15.247 (digital modulation, 2400 to 2483.5 MHz)	Certification, already granted to the module	Module FCC ID, "Contains FCC ID" on the host
Sub-GHz transmitter (intentional radiator)	15.247 (hopping, digital modulation or hybrid) or 15.249 (50 mV/m at 3 m) in 902 to 928 MHz	Certification, already granted to the module	Module FCC ID, "Contains FCC ID" on the host
Sensor digital circuitry (unintentional radiator)	Subpart B, Class B digital device	SDoC or certification (15.101)	SDoC records and compliance information statement

The digital part is not absorbed by the radio grants: 15.3(k) exempts the digital circuitry of a transmitter only when it is "used only to enable operation of the radio frequency device" and does not control other functions, and a sensor microcontroller that measures and logs does more than that. The SDoC responsible party must be located in the United States (2.909(b)), so a non-US manufacturer relies on its importer. The EU and US EMC logic is compared in CE vs FCC EMC, and the dual-market approach in EU and US dual certification.

Step 2: what the modules bring, and what the product adds

This is the step most worked examples get wrong. The two regions treat a module differently.

Item	EU (RED)	US (47 CFR)
Status of a module approval	No modular approval exists; the module maker declares the module, the sensor maker declares the sensor	Modular grant under 15.212, reusable within its grant conditions
Module test reports	Evidence the sensor maker may use in its file, if they cover the final configuration	Already part of the module grant
Finished product assessment	Required for every essential requirement, in all intended configurations (Article 17(1))	Subpart B for the host; 2.947(f) composite measurements with every source that emits at the same time actually emitting
Simultaneous BLE and sub-GHz operation	Part of the finished product assessment	Must stay within the module grant conditions, including RF exposure; otherwise a permissive change by the module grantee (2.1043(b)(4)) or a new certification
Label	CE marking on the sensor	"Contains FCC ID:" followed by each module FCC ID when not visible (15.212(a)(1)(vi)(A))
Restricted entities		Since FCC 25-71 (effective 26 December 2025), a covered modular transmitter, and any host that incorporates one, cannot be authorised (2.903)

Practical consequence: the module datasheet and grant conditions (antenna type and gain, host integration instructions, RF exposure conditions) are read before the layout is frozen, because leaving them is what turns a reuse into a new filing.

Step 3: the test plan

One plan covers both regions, with a column per region. The parameters below are those of the cited editions; the test plan template is in certification test plan template.

Test group	EU basis	US basis	What the text sets
BLE spectrum	EN 300 328 V2.2.2	15.247 (from the module grant)	EU: at most 20 dBm e.i.r.p.; non-adaptive equipment limited by Medium Utilisation (10 %)
Sub-GHz spectrum, 868.0 to 868.6 MHz	EN 300 220-2 V3.3.1, band of Decision 2006/771/EC		25 mW e.r.p., access techniques or a duty cycle of 1 % or less
Sub-GHz spectrum, 902 to 928 MHz		15.247 or 15.249 (from the module grant)	15.247: 1 W peak conducted with the hopping or bandwidth conditions; 15.249: 50 mV/m at 3 m
Radiated emissions of the radios	Inside the Article 3(2) standards, not EN 301 489	15.209 and the 15.247 or 15.249 limits	EN 301 489-1 excludes radiated emissions of radio equipment from its scope
Emissions of the digital circuitry	EN 301 489-17 and -3 (enclosure, auxiliary equipment)	Subpart B, 15.109 Class B, measured to ANSI C63.4-2014	US: composite device with both radios emitting (2.947(f))
Immunity	EN 301 489-17 and -3	No FCC immunity requirement	EU only
RF exposure	Assessment against 1999/519/EC (no cited standard fits)	1.1307(b)(3) exemption criteria, 1.1310 limits	US: 1 mW blanket exemption or the formula-based thresholds
Electrical safety	Article 3(1)(a), EN 62368-1 as other specification	Not an FCC matter	No voltage limit under the RED
Cyber	EN 18031-1, restrictions of 2025/138	No FCC requirement for this product	EU only

Measurement methods for US intentional radiators follow ANSI C63.10-2020, mandatory since 30 October 2025 (15.31, 15.38). The detail per standard is on RED tests, FCC tests and FCC standards.

Step 4: pre-compliance

Pre-compliance is informal testing by the development team before the formal campaign. No text requires it and it carries no presumption. For the Aurora ENV-1 it would cover, as a hypothetical plan:

1. Radiated emissions sweeps with a near-field probe to spot clock harmonics of the microcontroller and sensor bus.
2. Spurious and band-edge checks of both radios against the EN 300 328, EN 300 220-2 and 15.247 or 15.249 limits.
3. Both radios transmitting at the same time, the configuration 2.947(f) requires for the formal US measurement.
4. Electrostatic discharge on enclosure seams and on any accessible port.
5. A cyber gap review against EN 18031-1, starting with the authentication and update design, and a check that no option falls into a 2025/138 restriction.

Bench methods are covered in pre-compliance with TEM cell and near-field probes.

Step 5: the EU technical file and declaration of conformity

Under module A, the manufacturer draws up the technical documentation, keeps production compliant, affixes the CE marking and signs the EU declaration of conformity. The directive does not require an accredited laboratory for module A. Annex V lists nine elements, (a) to (i); the ones that shape this product file are:

1. Description, variants (EU868 build), photographs, user information including the frequency bands and maximum power required by Article 10(8).
2. Design and manufacturing drawings, schematics.
3. The list of harmonised standards applied with their references (EN 300 328 V2.2.2, EN 300 220-2 V3.3.1, EN 301 489-17 V3.3.1, EN 301 489-3 V2.3.2, EN 18031-1:2024) and the other specifications used (EN 62368-1, the RF exposure method).
4. Test reports, including module reports where they cover the final configuration.
5. The Article 3(3)(d) evidence, with the reasoning on why 3(3)(e) and (f) do or do not apply.
6. The explanation of Article 10(2) and 10(10): where the equipment may be used and whether restrictions apply.
7. A copy of the EU declaration of conformity.

The documentation and the declaration are kept for 10 years after the equipment is placed on the market (Article 10(4)). Details per element are in RED technical file and technical documentation file contents.

Step 6: the FCC side

With modules used within their grants, no new FCC ID is needed for the radios. The work on the US side is:

1. Read each module grant and its conditions; confirm antennas, power settings and simultaneous operation stay inside them.
2. Run the Subpart B measurement of the host as a composite device, both radios emitting (2.947(f)), with the ANSI C63.4-2014 method.
3. Issue the SDoC: the US responsible party keeps the test records and supplies with the product a compliance information statement giving the product identification, the 15.19(a)(3) statement and its US contact details (2.1077).
4. Label the host with "Contains FCC ID:" for each module and the 15.19 statement.

If the combination falls outside a module grant, two routes remain: the module grantee files a Class II permissive change (only the grant holder can, 2.1043(b)(4)), or the sensor maker applies for its own certification. That route needs an FRN, a five-character Grantee Code (fee due within 30 days, 2.926(c)), an FCC-recognised accredited laboratory, and a TCB, and the grant can be set aside within 30 days of publication (2.962(f)). The steps are in FCC procedure and FCC ID, grantee and TCB equipment authorization.

Step 7: labels and marks

Mark or identifier	Market	Text	Note for this product
CE marking	EU	RED Articles 19 and 20	On the equipment or its data plate, and on the packaging; no electronic alternative under the RED
Type, batch or serial number; manufacturer name and address	EU	RED Article 10(6) and 10(7)	On the product, or on packaging or documents where size does not allow
"Contains FCC ID:" for each module	US	15.212(a)(1)(vi)(A)	When the module FCC ID is not visible from outside
15.19(a)(3) compliance statement	US	15.19	On the device; in the manual and on the packaging only when the device is too small (15.19(a)(5))
E-label	US	2.935	Not available: the sensor has no display
Crossed-out wheeled bin	EU	Directive 2012/19/EU (WEEE), Article 14(4)	On the product; on packaging, instructions and warranty only in exceptional cases of size or function
Battery separate collection symbol	EU	Regulation (EU) 2023/1542, Article 13(4)	Since 18 August 2025; if it would be smaller than 0.47 × 0.47 cm on the cell, a symbol of at least 1 × 1 cm goes on the packaging
Battery labels ("non-rechargeable", minimum average duration)	EU	Article 13(1) and 13(3)	From 18 August 2026, or 18 months after the implementing act, whichever is later
QR code	EU	Article 13(6)	From 18 February 2027

The labelling choices are compared in e-label vs physical label.

Step 8: the coin cell

The battery brings three separate obligations:

• Removability. From 18 February 2027, Article 11(1) of 2023/1542 requires portable batteries to be "readily removable and replaceable by the end-user", with commercially available tools. Article 11(3) lifts this only where continuity of power supply is necessary and a permanent connection is required for safety or, "for products that collect and supply data as their main function, for data integrity reasons". A sealed sensor needs a documented reason that fits those words; a small or soldered cell is not one.
• Transport. UN 38.3 tests the cell or battery type, normally at the cell maker, not the sensor. The sensor ships as UN 3091 (lithium metal batteries contained in equipment), and the 2026 IATA guidance exempts button cells installed in equipment from the duty to make the test summary available. See IEC 62133 and UN 38.3.
• Producer responsibility. The battery management chapter, including batteries incorporated in appliances, applies since 18 August 2025. See EU Battery Regulation.

Other environmental files: RoHS, WEEE and REACH SVHC.

Step 9: cyber, now and after December 2027

The sensor is a product with digital elements under 2024/2847, the Cyber Resilience Act, as well as radio equipment under 2022/30. The two run in sequence:

Period	What applies	Text
From 1 August 2025	RED Article 3(3)(d) (and (e) if personal data are processed), presumption via EN 18031-1 and -2 within the restrictions	2022/30 as amended by 2023/2444; (EU) 2025/138
From 11 September 2026	CRA Article 14: actively exploited vulnerabilities and severe incidents reported, early warning within 24 hours	CRA Article 71
From 11 December 2027	CRA in full (Annex I requirements, conformity assessment, CE marking); 2022/30 repealed	CRA Article 71; (EU) 2026/339

EN 18031 is a CEN-CENELEC standard; EN 303 645, the ETSI consumer IoT baseline, is a useful reference but is cited neither under the RED nor under the CRA. See EN 303 645 IoT cyber security and Cyber Resilience Act (CRA).

Key dates for this product

Date	Event	Source
1 August 2025	RED Article 3(3)(d), (e), (f) applies; EN 18031-1, -2, -3 cited with restrictions	2023/2444, 2025/138
18 August 2025	Battery separate collection symbol; producer responsibility chapter	2023/1542, Articles 13(4) and 96
30 October 2025	ANSI C63.10-2020 mandatory for US intentional radiators	47 CFR 15.31, 15.38
11 December 2025	EN 300 220-2 V3.3.1 cited	(EU) 2025/2499
26 December 2025	Covered modular transmitters cannot be authorised	FCC 25-71, 2.903
18 August 2026	Battery labels, or 18 months after the implementing act if later	2023/1542, Article 13
11 September 2026	CRA reporting obligations	CRA Article 71
18 February 2027	Portable battery removability; battery QR code	2023/1542, Articles 11 and 13(6)
11 June 2027	EN 300 220-2 V3.1.1 loses presumption	(EU) 2025/2499
11 December 2027	CRA applies in full; 2022/30 repealed	CRA Article 71, (EU) 2026/339

Claims the texts contradict

Several of these were made by an earlier version of this page.

Claim	What the text says
"EN 62368-1 is the harmonised standard for RED Article 3.1(a)."	The RED list cites only EN 50360, EN 50566, EN 50385 and EN 50401 under 3(1)(a). EN 62368-1 is cited under the LVD (EN 62368-1:2014 + AC:2015) and is used under the RED as another specification.
"EMC: the EN 301 489 series, with EN 55032."	EN 301 489-1 is not cited on its own; the presumption comes from the specific parts, here -17 V3.3.1 and -3 V2.3.2 (Decision (EU) 2025/893). Radiated emissions of the radios belong to the Article 3(2) standard.
"EN 18031 is aligned with EN 303 645; RED 3.3 and the CRA lean on the same EN 303 645 provisions."	EN 18031 is a CEN-CENELEC standard cited with restrictions by Decision (EU) 2025/138. EN 303 645 is not cited under the RED or the CRA.
"No notified body is needed when harmonised standards are applied."	True for module A only when they are applied in full, and for EN 18031 only outside the 2025/138 restrictions (for example the password option).
"With two pre-approved modules, the product goes to a TCB for its FCC ID."	Modular grants are reused within their conditions with a "Contains FCC ID" label (15.212). A new certification or a permissive change is needed only if the integration leaves the grant conditions.
"RF exposure under the FCC is OET Bulletin 65."	The exemption criteria are in 47 CFR 1.1307(b)(3), with the limits of 1.1310.
"E-labelling may carry some of the marks on a small sealed enclosure."	47 CFR 2.935 allows an FCC e-label only on a device with an integrated display, and the RED has no electronic CE marking.
"The technical file is kept ten years after the last unit ships."	Article 10(4) says 10 years after the equipment has been placed on the market; the RED Guide counts from the last unit of the model.
"The coin cell drags in UN 38.3 testing of the product."	UN 38.3 tests the cell type; button cells installed in equipment are exempt from the test summary duty (IATA 2026).
"Battery and recycling marks" with no date or condition.	Separate collection symbol since 18 August 2025, labels from 18 August 2026 at the earliest, QR code from 18 February 2027, and a sealed cell needs an Article 11(3) reason from 18 February 2027.
"Design to market takes about six to nine months."	No text sets a duration. The figure was invented and has been removed.

Common pitfalls

Pitfall	Consequence	Avoid by
Assuming a module grant covers the product	Missing Subpart B authorisation, missing host label, simultaneous operation outside the grant	Reading grant conditions first; composite measurement under 2.947(f)
Expecting a RED "module approval"	File without finished product evidence	Declaring the finished product; using module reports only as evidence
Citing EN 62368-1 or EN 301 489-1 as RED harmonised standards	Wrong declaration, no presumption	Citing the RED list references; listing other specifications separately
Ignoring the gateway path for cyber	Article 3(3)(d) gap	Reading "directly or via any other equipment" in 2022/30
Offering a "no password" option	2025/138 restriction, notified body needed	Checking each EN 18031 option against the restrictions
Sealing the coin cell	Non-compliance from 18 February 2027	Designing for removal or recording the Article 11(3) reason
Planning an FCC e-label on a device without display	Label not compliant	Physical label, or manual plus packaging only for very small devices

Further reading

• RED checklist
• RED procedure
• FCC procedure
• FCC ID, grantee and TCB equipment authorization
• EU and US dual certification
• Certification test plan template
• EN 303 645 IoT cyber security
• Certification timeline
• Certification costs

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Sources and references

Sources & references

1. Directive 2014/53/EU (Radio Equipment Directive), EUR-Lex eur-lex.europa.eu/eli/dir/2014/53/oj
2. Delegated Regulation (EU) 2022/30, Article 3(3)(d), (e) and (f) of the RED, EUR-Lex eur-lex.europa.eu/eli/reg_del/2022/30/oj
3. Delegated Regulation (EU) 2023/2444, application from 1 August 2025, EUR-Lex eur-lex.europa.eu/eli/reg_del/2023/2444/oj
4. Delegated Regulation (EU) 2026/339, repeal of 2022/30 from 11 December 2027, EUR-Lex eur-lex.europa.eu/eli/reg_del/2026/339/oj
5. Implementing Decision (EU) 2025/138, EN 18031-1, -2 and -3 cited with restrictions, EUR-Lex eur-lex.europa.eu/eli/dec_impl/2025/138/oj
6. Implementing Decision (EU) 2025/893, EN 301 489-3 V2.3.2 and EN 301 489-17 V3.3.1 cited, EUR-Lex eur-lex.europa.eu/eli/dec_impl/2025/893/oj
7. Implementing Decision (EU) 2025/2499, EN 300 220-2 V3.3.1 cited, V3.1.1 withdrawn from 11 June 2027, EUR-Lex eur-lex.europa.eu/eli/dec_impl/2025/2499/oj
8. ETSI EN 300 328 V2.2.2 (2019-07), 2.4 GHz wideband data transmission, ETSI www.etsi.org/deliver/etsi_en/300300_300399/300328/02.02.02_60/en_300328v020202p.pdf
9. ETSI EN 300 220-2 V3.3.1, short range devices in the 25 MHz to 1 000 MHz range, ETSI www.etsi.org/deliver/etsi_en/300200_300299/30022002/03.03.01_60/en_30022002v030301p.pdf
10. 47 CFR Part 15, radio frequency devices, eCFR www.ecfr.gov/current/title-47/chapter-I/subchapter-A/part-15
11. 47 CFR 15.101, equipment authorization of unintentional radiators, eCFR www.ecfr.gov/current/title-47/chapter-I/subchapter-A/part-15/subpart-B/section-15.101
12. 47 CFR 15.247, operation within the bands 902-928 MHz, 2400-2483.5 MHz and 5725-5850 MHz, eCFR www.ecfr.gov/current/title-47/chapter-I/subchapter-A/part-15/subpart-C/section-15.247
13. 47 CFR 15.249, field strength limits in 902-928 MHz and other bands, eCFR www.ecfr.gov/current/title-47/chapter-I/subchapter-A/part-15/subpart-C/subject-group-ECFR2f2e5828339709e/section-15.249
14. 47 CFR 15.212, modular transmitters, eCFR www.ecfr.gov/current/title-47/chapter-I/subchapter-A/part-15/subpart-C/section-15.212
15. 47 CFR Part 2, Subpart J, equipment authorization procedures (2.909, 2.925, 2.926, 2.935, 2.947, 2.962, 2.1043, 2.1077), eCFR www.ecfr.gov/current/title-47/chapter-I/subchapter-A/part-2/subpart-J
16. 47 CFR 1.1307, RF exposure exemption criteria (paragraph (b)(3)), eCFR www.ecfr.gov/current/title-47/chapter-I/subchapter-A/part-1/subpart-I/section-1.1307
17. Regulation (EU) 2023/1542 concerning batteries and waste batteries, EUR-Lex eur-lex.europa.eu/eli/reg/2023/1542/oj
18. Directive 2012/19/EU on waste electrical and electronic equipment (Article 14(4), Annex IX), EUR-Lex eur-lex.europa.eu/eli/dir/2012/19/oj
19. Lithium Battery Guidance Document, 2026 (based on the 67th edition of the IATA DGR), industry guidance, IATA www.iata.org/contentassets/05e6d8742b0047259bf3a700bc9d42b9/lithium-battery-guidance-document.pdf
20. Regulation (EU) 2024/2847 (Cyber Resilience Act), EUR-Lex eur-lex.europa.eu/eli/reg/2024/2847/oj