When a 60950-1 certified internal power supply is used in an end product, is it required that internal components of power supply – capacitors, GDTs, etc. - meet 62368-1 clause 18.104.22.168 / 5.5.7’s electric strength requirement?
In the case of a 60950-1 certified internal power supply that already has had its capacitors, GDTs, etc. evaluated as part of the original power supply investigation / certification, additional electric strength testing per Clause 22.214.171.124 (referenced in 126.96.36.199 / 5.5.7) in 62368-1 is not required again on capacitors, GDTs, etc. during the end-use product investigation to 62368-1.
Sub-clause 4.1.1 of 62368-1 is intended to facilitate a smooth transition from the legacy standards, 60950-1 and 60065, to 62368-1. Therefore, the critical components inside of a 60950-1 or 60065 certified power supply do not need to be revisited by 62368-1. The rationale of acceptance of components and their requirement from legacy standards is further explained in the informative (explanatory) document IEC TR 62368-2, which may be accessed from the IEC Webstore and similar sources - https://webstore.iec.ch/publication/65059 .
Also, the IEC TC108 interpretation panel question 108/698/INF gives guidance for component acceptance per 4.1.1 with some examples in various situations. Although this particular question was not addressed exactly, it will be helpful for further understanding of the application of 4.1.1, and the document is available through IECEE website - https://decisions.iecee.org/iecee/SearchCMC.nsf/de_h.xsp?v=iectc .
Finally, please note, regarding the legacy component paragraph in question in 4.1.1, per the Note to 4.1.1 of IEC 62368-1:2018, “The paragraph above will be deleted in the next revision of this document, subject to a vote of National Committees at the time. It is added here to provide a smooth transition from the latest editions of IEC 60950-1 and IEC 60065 to this document.” Therefore, use of legacy 60950-1 power supplies to comply with 62368-1 has a limited lifetime and manufacturers should consider transitioning their power supplies to 62368-1.