USB Power Delivery now supports up to 240W through the Extended Power Range (EPR) specification. That headroom has created a specific sourcing problem: a cable printed with a high wattage number doesn’t guarantee it can deliver that power safely, because the number on the packaging and the chip inside the cable are two different things — and verifying which one you’re actually getting requires knowing what to ask a Chinese cable manufacturer for.
Why the Cable’s Chip Is the Real Spec
Under the USB-IF specification, any USB-C cable rated above 3A (roughly 60W) must contain an e-marker chip — a small chip in the connector that reports the cable’s actual current-carrying capability to the charger and device during negotiation. A cable without a genuine, correctly-provisioned e-marker cannot legitimately be authorized to carry higher current, regardless of what’s printed on the sleeve or packaging.
This isn’t a niche component. Chongdiantou (充电头网), an independent teardown lab that has disassembled and published test reports on cables since 2016, has torn down over 100 cable products specifically to document what chip is actually inside. In one batch of 62 e-marker-equipped cables it examined, Hynetek (慧能泰)’s HUSB332 series accounted for the largest single share at 29%, with VIA Labs (威锋电子)’s VL152 also appearing frequently — meaning there’s a small, identifiable set of legitimate chip suppliers a factory should be able to name specifically, not a vague “we use certified components” answer.
A Parallel Case Worth Knowing: The Power Bank Certification Investigation
E-marker fraud doesn’t happen in isolation from China’s broader certification enforcement environment. In March 2026, a Guangming Daily investigation into power bank CCC certification found that at least one OEM factory continued production under a brand’s certification even after that specific certification had been suspended by regulators — the sales team was still active and the production line was still running when reporters visited in person, despite the certificate no longer being valid.
China’s regulators responded with a new requirement, phased in from March 2026: newly certified power banks must carry a CCC mark paired with a traceable QR code, checkable against the official certification platform, specifically to close the gap where a printed certification mark could no longer be trusted to reflect current, valid status. The same underlying problem — a printed mark that doesn’t reliably reflect what’s actually inside or what’s currently valid — applies just as directly to e-marker chips in charging cables, even though no equivalent QR-traceability requirement exists yet for that category specifically.
What to Ask a Cable Supplier
- Ask for the specific e-marker chip brand and model — not just “USB-IF certified.” A legitimate factory can name it (Hynetek HUSB332, VIA Labs VL152, and similar are common, verifiable options); a vague answer is itself a signal.
- Cross-check the product against Chongdiantou’s published teardown reports where available, or request teardown photos showing the chip’s printed markings directly, rather than relying on box-printed wattage alone.
- For 240W (PD 3.1) cables specifically, confirm the chip supports the newer negotiation requirements — commonly referred to as E-Marker 2.0 — since older-generation chips can’t participate correctly in the dynamic power negotiation newer high-wattage devices use, which caps real-world charging speed regardless of the cable’s printed rating.
- Request or perform an actual load test rather than trusting a basic USB tester reading alone — a spoofed or miscoded chip can report a false rating to consumer-grade testers; a proper load test measures real current delivery under sustained draw.