If a product is using a power supply certified to IEC 60950 or IEC 62368, with direct connection to the appliance mains inlet, does the 'Stored discharge on capacitors' test of 126.96.36.199 still have to be done?
A variety of AV/ICT equipment utilize a modular (or similar) form factor power supply with an appliance inlet for connection to the a.c. mains directly incorporated into the power supply. For these constructions the appliance inlet is the only connection to the a.c. mains and all of the filtering and discharge components, including X & Y capacitors and discharge resistors, are in the power supply. As a result, it is reasonable to assume the overall system contribution outside the power supply would have negligible influence on compliance of the system with 188.8.131.52, Capacitor discharge after disconnection of a connector.
Therefore, if a 62368-1 certified power supply used per its ratings is incorporated into a larger system and the power supply has already had the investigation conducted per 184.108.40.206, there should be no need to repeat the test on the larger system during the system’s 62368-1 investigation.
However, you also mentioned the example of a IEC 60950 power supply incorporated into a system being investigated to IEC 62368-1. Because of the legacy component provision in 4.1.1 of IEC 62368-1, which allows for incorporation of 60950-1 (and 60065) components into 62368-1 equipment / systems without additional evaluation of the component, the evaluation per 220.127.116.11 of IEC 62368-1 also should not need to be repeated for this case. As mentioned in a past answer in this Forum, the IEC TC108 interpretation panel question 108/698/INF gives guidance for component acceptance per 4.1.1, with some examples for various scenarios, including specifically 18.104.22.168 as an example. Reviewing this interpretation would be helpful for further understanding of the application of 4.1.1 - the document is available through IECEE website (search for ‘108/698/INF’) - https://decisions.iecee.org/iecee/SearchCMC.nsf/de_h.xsp?v=iectc.