Jim Eichner <[email protected]> wrote (in <[email protected]>) about 'Protection against direct contact in 60950-1', on Tue, 29 Nov 2005: >Q4: If the answer to Q1 is a), what is the justification for only >requiring no contact as opposed to enforcing creepage and clearance? Is >it related to the fact that the person's finger will only be there >briefly, making it unlikely that breakdown of the small gap between >the finger and the live part would occur?
Not only that, but the area of contact could only be very small, and people don't often push their fingers into connectors these days. I had a long argument with a connector manufacturer a few years ago about this, when the requirements in IEC/EN 60065 (and, I think, IEC/EN 60950)were less clear and, with a certain contrived interpretation, required connector contacts to be recessed 4 mm minimum, thus making many widely-used connectors non-compliant. I believe it was this matter that led to the later clarification in both standards - no clearance required below a certain fairly high voltage. In this particular case, it's difficult to see how creepage could be less than clearance. BUT I don't think you should use a connector that can be opened without using a tool to contain hazardous voltages. -- Regards, John Woodgate, OOO - Own Opinions Only. Deadlines are 90% of deadliness. http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas [email protected] Mike Cantwell [email protected] For policy questions, send mail to: Jim Bacher: [email protected] David Heald: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
