Kristiaan – Most of the responses agree with my understanding.
I will add that my recollection of the origins of the test in 60950 was related to electrical connections under compressive loading where the compression is needed to establish and ensure an electrical connection. Some custom made terminal blocks were made using inexpensive materials, including polyamide without inorganic fillers (like glass). As time moved on, the application of the testing expanded to cover other design features. http://www.ulttc.com/en/solutions/test-methods/physical/ball-pressure-test.html It appears the testing was simplified to a single temperature with the pass/fail criterion simply being the 2.0 mm diameter dimple, rather than finding the temperature at which the 2.0 mm dimple forms. Maybe Pete Perkins or Rich Knute recall further back than I do. Peter Tarver From: Carpentier Kristiaan [mailto:kristiaan.carpent...@technicolor.com] Sent: Wednesday, August 24, 2016 05:58 Hi group, Does any-one know the reason/background of the ball pressure test of thermoplastic parts (IEC60950-1, clause 4.5.5) and the chosen temperature of 125C. This test is performed - for example – on the plastic parts of a direct plug-in power supply as these parts “carry” the mains power supply pins. I can’t imagine a situation there that requires such a test and certainly not at 125C. Thanks for your feedback! Best regards Kris Carpentier - The information contained in this message may be privileged and confidential. It is intended to be read only by the individual or entity to whom it is addressed or by their designee. If the reader of this message is not the intended recipient, you are on notice that any distribution of this message, in any form, is strictly prohibited. If you have received this message in error, please immediately notify the sender and delete or destroy any copy of this message! - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <emc-p...@ieee.org> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <sdoug...@ieee.org> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher: <j.bac...@ieee.org> David Heald: <dhe...@gmail.com>
