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Ron, I don't know what the origin of the 45 uC limit is, but I am sure that it has to do with what would be a sustainable source to deliver a shock. Common static electricity is at a very high voltage, but the continued charge is not enough deliver a shock that would injure a person. The limit must have its origins in experimentation on "bodies". Fortunately, you do not have to worry about measuring uC anymore, because clause 2.4.2 was changed in IEC 60950-1 so that now you measure circuit capacitance in nF for voltages between 0.45kV and 15kV. Apparently, the thing that used to be done was to measure the capacitance, then convert to coulombs. Best Regards, Don Gies Product Compliance Engineer Lucent Technologies - Bell Labs Holmdel, NJ 07733 USA From: [email protected] [mailto:[email protected]]On Behalf Of Ronald R. Wellman Sent: Thursday, July 29, 2004 8:58 AM To: [email protected] Subject: Origin of 45 micro coulomb limit http://www.ieee-pses.org/symposium http://www.emc2004.org/ Hello all, I was wondering if anyone knows of the origin of the 45 micro coulomb limit used to specify the charge of capacitance level under normal conditions for voltages up to 15 kV? Does this value come from scientific data or some other standard? Example standard clauses are: IEC 61010-1, clause 6.3.1 (c) (1) and IEC 60950-1, clause 2.4.2. Best regards, Ron Wellman This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. IEEE PSES Main Website: http://www.ieee-pses.org/ To post a message send your e-mail to [email protected] Instructions for use of the list server: http://listserv.ieee.org/listserv/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Ron Pickard: [email protected] Dave Heald: [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. IEEE PSES Main Website: http://www.ieee-pses.org/ To post a message send your e-mail to [email protected] Instructions for use of the list server: http://listserv.ieee.org/listserv/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Ron Pickard: [email protected] Dave Heald: [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
