Decoding Part 15B and SDoC Requirements for US Market Entry
Every EV charger containing a microcontroller or digital logic circuit is classified by the US Federal Communications Commission as an unintentional radiator. These devices must strictly comply with FCC Part 15B limits for both conducted and radiated electromagnetic emissions.
Since 2017, the FCC streamlined compliance for most unintentional radiators by introducing the Supplier’s Declaration of Conformity (SDoC). Under SDoC, the responsible party—typically the US importer or a designated US agent—self-declares compliance based on empirical test results. We do not submit technical files to the FCC for an official approval grant, which significantly reduces administrative overhead. Traditional FCC Certification, which requires filing with a Telecommunication Certification Body, is now generally reserved for intentional radiators, such as Wi-Fi or cellular-enabled smart chargers.
Our US standard portable chargers, such as the CREVC-JT2G132, deliver 7.0kW at 32A using Type 1 (SAE J1772) connectors across an AC100-240V range. The physical connector guarantees mechanical compatibility, but we design the internal control boards to suppress electromagnetic interference and satisfy Part 15B limits.
When evaluating a potential manufacturing partner for the US market, use this pass/fail checklist:
- Pass: The supplier clearly understands SDoC documentation requirements and can explain the legal responsibilities of the US importer.
- Pass: They know the exact difference between SDoC for basic digital logic and traditional FCC Certification for wireless modules.
- Pass: They supply verified US-standard connectors, specifically Type 1 / SAE J1772 or NACS, alongside compliant control boards.
- Fail: The supplier confuses FCC Part 15B emissions limits with CE EMC directives, treating them as identical tests.
- Fail: They incorrectly suggest that traditional FCC Certification is mandatory for all standard, non-wireless EV chargers, which will unnecessarily inflate your compliance costs.
Verifying In-House PCB Design and Emission Control Capabilities
FCC Part 15B compliance lives or dies on the printed circuit board. Digital logic circuits and microcontrollers inside the charger generate high-frequency noise. If the board layout is poor, this noise radiates past legal limits. We design and manufacture our own PCBs in-house at our Wenzhou production base. This gives our engineers direct control over trace routing, ground plane integrity, and component placement to suppress electromagnetic interference before the first prototype is built.
The physical footprint adds another constraint. Our control box measures exactly 235mm x 99mm x 52mm, requiring us to pack the PCB tightly while maintaining adequate clearance for high-voltage traces and EMI filtering components. When a board fails an initial radiated emissions sweep, assembly-only factories must send it back to a third-party designer, adding weeks to the project. Because we handle PCB R&D internally, our engineers can immediately tweak the layout. Adjusting the decoupling capacitor placement near the MCU on our CREVC-JT2G132 US Standard Portable Charger control board, for instance, helps us easily clear the 30 MHz to 1 GHz Class B limits. Our IATF 16949 certification requires strict documentation of all these design iterations.
Once the board passes internal PCB function testing, it moves to assembly, followed by 100% aging and load testing to ensure thermal stability does not degrade the EMI filters over time.
Evaluate a supplier’s engineering depth using this checklist:
- Pass: The factory designs their own control boards and employs dedicated EMI engineers who can modify component placement during the design phase.
- Pass: They perform internal PCB function testing and strict incoming material inspection on all electronic components before assembly.
- Fail: The supplier relies on off-the-shelf, unverified third-party PCBs and cannot explain how they manage conducted and radiated emissions at the board level.
- Fail: They lack the in-house engineering staff to troubleshoot Part 15B failures, meaning any test failure requires outsourcing the fix to an external lab.
Evaluating Test Lab Partners and Validating FCC Documentation
Securing FCC Part 15B compliance requires more than just a well-designed control board. You need verifiable test data from a competent facility. Under the Supplier’s Declaration of Conformity (SDoC) process, the manufacturer self-declares compliance, but this declaration must be backed by actual test results. We route our US-market portable chargers, such as the CREVC-JT2G132, through ISO/IEC 17025 accredited laboratories to ensure our Part 15B emission limits are independently validated before shipping.
Evaluate your supplier’s testing partnerships using this checklist:
- Pass: The supplier uses an ISO/IEC 17025 accredited test lab. This specific accreditation guarantees the facility operates with documented quality management and proven technical competence.
- Pass: They provide clear, unredacted test reports specifically detailing Part 15B conducted and radiated emissions, rather than just a generic compliance summary.
- Pass: They demonstrate a consistent track record of passing US physical and electrical standards, such as SAE J1772, alongside FCC requirements.
- Fail: The supplier cannot produce valid, traceable test reports for the exact charger model you are purchasing.
- Fail: They rely on unaccredited, low-cost testing facilities just to secure a quick pass mark. This leaves your company legally liable if Customs or the FCC audits the shipment.
- Fail: They provide altered or forged certificates. We verify every report against the lab’s online database; you must do the same.
A legitimate factory will happily share their test reports during the initial quotation stage. If they hesitate, walk away. Furthermore, strict incoming material inspection of EMI shielding components ensures the physical mass-produced units match the lab-tested prototype, keeping your SDoC legally valid.
Auditing the Factory’s QC Workflow and Aging Test Protocols
Passing Part 15B in an isolated test lab means nothing if the assembly line compromises the design. A charger that meets FCC limits on day one will fail on day one hundred if the factory silently swaps EMI shielding components for cheaper alternatives during mass production.
You need a factory that treats the Bill of Materials as a locked document. A locked BOM is non-negotiable. At our Wenzhou facility, we enforce strict component traceability from the incoming material inspection right through to final packaging. If a reel of capacitors or ferrite beads changes, the engineering team must re-verify the emissions profile.
Evaluate their QC workflow against this checklist:
- Incoming material inspection: Verifies EMI gaskets and shielding materials match the approved prototype.
- PCB function testing: Checks microcontroller logic before the board goes into the 235×99×52mm control box.
- 100% aging/load testing: We run every unit at full 32A load for a minimum of four hours to catch early component failures and thermal drift.
- Dielectric withstand (hipot) testing: Ensures isolation between high voltage and low voltage circuits.
- Grounding continuity check: Critical for electrical safety and ensuring the metal chassis acts as a proper RF ground plane to contain emissions.
Pass the supplier if they maintain this sequence and back it up with a standard 24-month warranty. Our IATF 16949 certification requires us to document every process step, making unauthorized substitutions practically impossible.
Fail the supplier immediately if they cannot explain how they prevent component swapping, or if they refuse to let you audit their incoming inspection records for EMI parts. Trading companies and loose factories will happily build a compliant prototype, then quietly downgrade the internal shielding to improve their margin on a 500-unit order.
Finalizing MOQs, Lead Times, and Spotting Procurement Red Flags
Getting the commercial terms right is just as critical as the technical specs. When you source a US-standard unit like our CREVC-JT2G132 portable charger, you need realistic expectations for volume and delivery.
At the Wenzhou facility, we set the Minimum Order Quantity at 50 units per model for branded orders, and 100 units for full OEM private-label runs. Production lead time sits at 25 to 35 days for standard builds. If you require custom cable lengths or specific enclosure colours, add another 5 to 10 days, bringing the total to 30-45 days.
Watch out for these procurement red flags during the quoting phase:
- The ‘Trading Company in Disguise’: If the supplier cannot show you their in-house PCB assembly line or refuses to explain their incoming material inspection process for EMI filters, you are likely dealing with a middleman. They lack the engineering control to guarantee consistent FCC Part 15B compliance across batches.
- The ‘7-Day FCC Miracle’: Any supplier promising a 7-day turnaround for FCC Part 15B testing is lying. Proper radiated emissions testing at an accredited lab takes time. Rush jobs mean they skipped the pre-scan or faked the report.
- Vague Pricing on Shielding: If a quote is significantly cheaper than the market average, check the bill of materials. Proper EMI shielding components—like ferrite cores and common-mode chokes—cost money. Suppliers who exclude these to win the contract will fail the emissions test or cause interference in the field.
Always demand a detailed breakdown of the bill of materials. We confirm feasibility and provide a firm delivery schedule within 48 hours of receiving your requirements brief. If your current supplier gives you the runaround on lead times or hides their manufacturing reality, it is time to look elsewhere.
Common Questions from B2B EV Charger Buyers
Does the Supplier’s Declaration of Conformity (SDoC) legally require a third-party test lab?
Technically, no. SDoC is a self-declaration process. However, we strongly advise using an ISO/IEC 17025 accredited laboratory. Relying on unaccredited facilities often yields inaccurate Part 15B emission data, leaving your company holding the liability if the FCC audits your product. We perform internal PCB function testing at our Wenzhou facility to catch EMI issues early, but final SDoC validation requires independent, accredited data to protect your supply chain.
Can we simply import our existing CE-certified chargers to the US market?
No. CE marking covers European EMC directives, which have different frequency limits and testing methodologies than US regulations. The American market strictly enforces FCC Part 15B limits for unintentional radiators. Furthermore, your hardware must physically comply with SAE J1772 or NACS standards. Our US-standard CREVC-JT2G132 portable charger, for instance, uses a Type 1 connector and handles 100-240V single-phase AC. The 235×99×52mm control box is specifically engineered to meet North American physical and electrical requirements, which differs entirely from our EU Type 2 models.
Who holds legal responsibility for the SDoC documentation?
The legal burden falls squarely on the US importer. If a foreign manufacturer is importing directly without a domestic partner, they must designate a US-based agent to accept legal responsibility. This agent must maintain the compliance records and test reports on file for at least five years. Failure to maintain these records can result in severe penalties and product seizure at the border.
Before finalizing your procurement contract, always verify that your manufacturing partner provides transparent SDoC documentation and valid Part 15B emission test reports for the US market. If you need expert guidance vetting suppliers or navigating the FCC certification process for your EV chargers, our engineering team is ready to help. Connect with us on our contact page to ensure your next deployment is fully compliant and ready for market entry.
