Bill, Thanks for the reply. I guess different product safety standard has different requirements for the voltage on plug pins. I think that the IEC 60950 standard requires the pin voltage to drop below 37% of the peak voltage within the first second.
We always did the 60 volt 5 second test for Laboratory Equipment. Maybe the standards writers think people who work in a lab is smart enough not to touch the pins or that they can handle shocks without mutating into a super hero. (I see a movie plot developing here). What gets me scratching my head is the chart on Figure 3 and why is starts at 100 volts. Am I to interpret the requirements to mean that if my 5 second voltage is below 100 volts that I can assume it passes? If so, I would really like to know. Can any of you safety expects help me out on this? Thanks, The Other Brian From: Bill Owsley [mailto:[email protected]] Sent: Tuesday, May 21, 2013 10:50 PM To: Kunde, Brian; [email protected] Subject: Re: Capacitor Discharge Test IEC 61010-1 A few decades ago when an intern, called co-op back then, a customer complaint came in that they had been shocked by the power plug after pulling it from the wall. No way said the engineers! Hey co-op go test this. Wellll.... it turns out there can be the peak voltage left on the pins of the plug which will decay depending on the environment. And so the bleeder resistor. I thought the time frame was on the order of 250 mS. How fast can an operator get their fingers on the plug pins after pulling out? Sticking their fingers on a partial pulled plugged was dis-allowed. But those details were for the Safety engineers. ________________________________ From: "Kunde, Brian" <[email protected]<mailto:[email protected]>> To: "[email protected]<mailto:[email protected]>" <[email protected]<mailto:[email protected]>> Sent: Tuesday, May 21, 2013 12:33 PM Subject: Capacitor Discharge Test IEC 61010-1 What we call the Capacitor Discharge Test in the IEC 61010-1 standard section 6.10.3 says that voltage across the pins of the power cord must not be Hazardous Live 5 seconds after disconnection from the supply. Most labs simply check to see if the voltage across the pins are 60 volts or less at 5 seconds, but the pass/fail criteria is the capacitive charge level described in 6.3.1 c) which is 45uC. 6.3.1 c) points you to "Line A of Figure 3" but this chart seems to start at 100 volts. So how do I apply this chart if my 5 second voltage is 80 volts? Am I looking at this wrong or should this chart go down to at least 60 volts? Is there a formula that can be used instead of the chart? In our specific case, we are measuring the discharge of an RF line filter which has 4.4uF of capacitance across the line and the 5 second voltage is 80 volts. My guess would be this filter fails as-is without and additional bleeder resistor but when I discuss it with the company they pick apart the standard and the chart at figure 3. Another question. When you perform this test what line voltage do you use? The highest nominal voltage or do you include +10%? For 230VAC equipment do you test at 230Vrms or 264Vrms (373Vpk)? Thanks to all for any input. The Other Brian ________________________________ LECO Corporation Notice: This communication may contain confidential information intended for the named recipient(s) only. If you received this by mistake, please destroy it and notify us of the error. Thank you. - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. 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If you received this by mistake, please destroy it and notify us of the error. Thank you. - ---------------------------------------------------------------- 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 <[email protected]> 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://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]>
