Peter, In my opinion this situation does not comply by virtue of the words, "- Capacitors shall not be connected between LIVE parts and non-PROTECTIVELY EARTHED ACCESSIBLE PARTS where the failure of such a capacitor could result in ACCESSIBLE PARIS becoming LIVE." Since your power supply is double insulated, I would presume that any conductive parts on the secondary side are not protectively earthed.
Capacitors complying with IEC 60384-x are only accepted where conductive parts are also protectively earthed. "- Capacitors connected directly between the MAINS PART and PROTECTIVELY EARTHED ACCESSIBLE METAL PARTS shall comply with the requirements of IEC Publication 384-14 or equivalent." You might find it helpful to use the 2006 version of the standard as that has made significant efforts to align certain parts with IEC 60950-1. I would also comment that there are manufacturers of plug-in or lump-in-a-cord power supplies who have products certified to IEC 60601-1, so why go to the trouble of trying to use a 60950-1 certified device? If you contact me directly, I can point you towards such a manufacturer. Best regards Neil R. Barker CEng MIET FSEE MIEEE Manager Quality Engineering e2v technologies (uk) ltd 106 Waterhouse Lane Chelmsford Essex CM1 2QU UK Tel: (+44) 1245 453616 Fax: (+44) 1245 453571 Mob: (+44) 7801 723735 P Please consider the environment before printing this email. From: Tarver, Peter [mailto:[email protected]] Sent: 16 April 2007 19:47 To: PSTC 1 Subject: UL 60601-1, §56.4 Good morning. A customer is intending to use a direct plug-in power supply that is certified using the 60950-1 standards to supply a medical device. The power supply is double insulated and marked with IEC 60417, Symbol 5172. I am doing a gap analysis on this power supply. This power supply has a capacitor (marked with sundry safety agency logos and with, "X1 Y1," [which will be assumed true for the purposes of this question]) that bridges primary and secondary circuits. Do (or can) Y1 capacitors in such applications comply with §56.4, first dashed paragraph? UL 60601-1 does not overtly give credit for IEC 60384-x capacitors. In Appendix A of UL 60601-1, the rationale for §56.4 states, "Such capacitors cannot provide DOUBLE INSULATION or REINFORCED INSULATION." Regards, Peter L. 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