Power Adapter Efficiency: DoE Level VI and EU CoC Explained
Efficiency marks are not marketing. In the US, external power supplies must meet DoE Level VI; in the EU, the Code of Conduct Tier 2 (2016) sets the bar. Miss them and the product cannot be legally imported.
DoE Level VI (United States)
The US Department of Energy sets mandatory efficiency for external power supplies. Level VI requires a rising average active-mode efficiency (roughly 87-89% depending on power) and a no-load draw of 0.1W or less for supplies up to 250W. It applies to both single-voltage and multi-voltage adapters.
EU Code of Conduct Tier 2
The EU CoC (often referenced alongside the ERP Lot 9 rules) sets similar active-mode thresholds and a 0.15W-or-better no-load limit for many classes. It is the de-facto bar for selling into Europe alongside the CE mark.
Why No-Load Power Matters
An adapter left plugged in with nothing connected still draws. At scale - millions of CCTV cams and routers - 0.5W each is real grid load. Sub-0.1W standby is now the compliance floor, not a premium feature.
Buying Implication
Specify a certified Level VI / CoC supply and keep the certificate on file. Customs and buyers increasingly ask for it. XGW adapters are marked and tested to these levels.
FAQ
Does a higher efficiency rating mean a hotter adapter?
Usually the opposite: a more efficient supply wastes less as heat, so it runs cooler for the same output.
Are Level VI and CoC the same test?
No, but they track closely. A supply certified to Level VI almost always meets EU CoC Tier 2; confirm the specific certificate for the exact model.
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