Power Supply Basics

IEC/UL/EN 60950-1 Amendment 2

Posted by Dulcie on October 6, 2015
Posted in: Power Supply Basics

In August 2013, CENELEC published Amendment 2 to EN 60950-1:2006 covering the general safety requirements of ITE (Information Technology Equipment). July 2nd, 2016 is the expiry date for Amendment 1 of EN 60950-1, and manufacturers are working through their 60950-1 reports to update their files.

For Europe, this amends EN 60950-1:2006 and its Amendments 1 and 12. Safety files will now state EN 60950-1:2006/A2:2013 or EN 60950-1:2006 + A11:2009 + A1:2010 + A12:2011 + A2:2013. It has been widely stated that this will be the last change to the 60950-1 standard.

Oct 14, 2014 was the publication date by UL and CSA for the update to UL/CSA 60950-1 and safety files will now refer to UL 60950-1, 2nd Edition, 2014-10-14 and CAN/CSA C22.2 No. 60950-1-07, 2nd Edition, 2014-10. In UL/CSA’s case, upgrading to Amendment 2 is not mandatory on existing product files.

With the upcoming June 2019 transition to IEC 62368-1:2014 for both IEC 60950-1 and IEC 60065, what was changed? Fortunately for the power supply manufacturers, the changes to IEC 60950-1 are mainly “clarifications”. Both TÜV Rheinland® and UL reported that in general there would be no impact requiring product changes and/or that it was reflecting their current practice.

For IEC 60950-1 the main changes for power supplies are:

  • Clause requires that any graphics used are to comply with ISO standards and should be explained in the manual. These include some (not widely used) earth grounding symbols.
  • Clause 2.9.2 introduced humidity testing to equipment designated for tropical regions. Chinese CCC and CQC safety standards have been concerned about this for some time.
  • Likewise 2.10.3 refers to a common requirement in China for a higher maximum altitude, typically 5,000m, or the addition of a symbol indicating operation at a maximum of 2,000m. This is not an issue for UL, EN or CB.
  • Clause 4.3.8 requires non lead acid batteries to comply with IEC 62133, with the exception of button style batteries. This will only affect a very limited number of power supplies.
  • The use of VDRs (voltage dependant resistors), which was a major change for Edition 1, have had a flammability requirement added.

Indeed this amendment is widely seen by the safety bodies as a way to ensure a smoother transition into IEC 62368-1:2014.