Amendment No. 2 to IEC 60950-1 Second Edition, Safety of Information Technology Equipment, was published in May 2013. The differences as compared to Amendment 1 (and UL 60950-1 2nd Edition) are mostly minor, but there are a few notable changes.
Note that IEC Technical Committee (TC) 108 has made a commitment to limit revisions to IEC 60950-1 and concentrate its work and effort on IEC 62368-1, Audio/video, information and communication technology equipment – Part 1: Safety requirements, the Standard that will eventually replace IEC 60065 (AV Equipment) and IEC 60950-1 (ICT Equipment) (See our FAQs regarding 62368-1 post). Therefore, most of these changes were adopted to allow for continued effective application of IEC 60950-1 during the transition.
The CSA/UL version of 60950-1 based on Amendment No. 2 likely will be published by mid-year 2014.
Following are the three notable changes, one less onerous, two potentially more onerous.
Clause 4 (Physical Requirements)
Sub-clause 4.3.8 (Batteries) now includes a reference to IEC 62133 for portable secondary sealed cells and batteries (other than button) containing alkaline or other non-acid electrolyte, which includes Lithium-Ion. Also, the criteria for overcharging of a rechargeable battery were modified to reflect some of the work done on IEC 62368-1 to make a more realistic test condition.
The new IEC 62133 requirement could have a considerable negative impact on manufacturers who were able to use IEC 60950-1 for such batteries in the past, although it is muted by the existing U.S. and Canada National Difference requiring UL 2054 for most of these same types of batteries.
Clause 7 (Connection to Cable Distribution Systems)
Sub-clause 7.4.1 (General) now allows for similar protection of TNV-1 circuits as is currently allowed in 7.3, and therefore such circuits do not need to be subjected to voltage surge test in 7.4.2 or impulse test in 7.4.3.
This change provides additional design options for equipment connected to the cable distribution network and involving SELV voltage levels and that are intended to be earthed on the secondary side.
Annex Q – Voltage Dependent Resistors (VDRs)
Annex Q was updated to include additional information that was added to Edition No. 2 of IEC 62368-1.
Because the previous Annex Q was lacking detail, there may be a negative impact on manufacturers who previously specified VDRs that do not meet the updated criteria. There still remains some uncertainty on the true impact of this change at this time, including the provision for flammability of the VDR body.
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