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As for the IEC62368-3:2017, the test methods for specified ports (USB or PoE) under different conditions are not clear. Will these parts be clarified?

More specifically you asked, as for the IEC62368-3:2017, the test methods for specified ports (USB or PoE) under different conditions are not clear. Will these parts be clarified in the coming UL62368-3 ? Or should we refer to the port standard(USB or IEEE802.3) to design the test details ourselves?


In response, as for the IEC62368-3:2017, there will not be any clarifications (national differences) coming in UL 62368-3.  In fact, the CAN/US Technical Harmonization Committee (THC) has made a decision not to pursue a CSA/UL 62368-3 standard in Canada and the U.S. for its first edition.  Instead, there will be a direct reference to IEC 62368-3 in CSA/UL 62368-1 Edition No. 3, which has a target publication date of 4Q 2019.

Regarding the statement made that “the test methods” are not clear,  to answer in detail we would need to know more information on which parts of the test methods are unclear to you.


Most of the content on measurements in Clause 5 of IEC 62368-3 are for voltage and/or current measurement and are in accordance with Clauses 5.2, 6.2, Annex Q of IEC 62368-1.  They are general voltage / current measurements, so that the methodology of the measurements would seem to be relatively clear.


If the statement about not being clear is related to the ambiguity of the limit values as compliance criteria within clause 5.3.2, this topic has been discussed in IEC TC108/HBSDT.  Most of the limits in Clause 5, other than from IEC 62368-1, are from the USB, IEEE 802.3, and similar industry specifications.  So, yes, manufacturers should refer to the industry port standards (USB or IEEE802.3) for the details.  IEC TC108 expects this.

Also, IEC TC108’s Interpretation panel has issued an interpretation on Clause 5 as Q9 – it has been issued as 108/722/INF to clarify the determination of the available output power in Clause 5.3.2. We hope this TC108 Interpretation will be of a help in understanding the limit values in clearer manner.  (It is expected that the interpretation soon will be shared at IECEE CTL site.)


Since the requirements in Clause 5 of IEC 62368-2 are not country-specific matter, it is expected IEC-based National Standards (like UL) will not adopt National Differences for these kinds of matters.  Therefore, concerns with IEC 62368-3 ideally should be brought directly to IEC TC108 through your national committee.  Then, if consensus within IEC TC108, revisions to the standard can be considered, or Interpretations like previously mentioned above can be issued.


Since IEC 62368-3 is a new standard, and it is likely you may have more questions that are design-dependent, we suggest that you contact the UL office you work with and request a consult if you have a specific design or construction that you wish to discuss.

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