I haven't thought this through completely, but it seems to me anytime you take two bodies (one being the power mains or some other voltage source, and one being a person at an unknown charge level) and bring them together, there will be some kind of charge equalization -- i.e., current flows from one to the other... To have the current continue to flow then requires a circuit -- a closed path........
Best Regards, Michael Hopkins Manager, Customer Technical Center Control Technology Division Compliance Test Solutions Thermo Electron Corporation One Lowell Research Center Lowell, MA 01852 Tel: +1 978 275 0800 ext. 334 Mobile: +1 603 765 3736 michael.hopk...@thermo.com One Thermo, committed to integrity, intensity, innovation & involvement From: owner-emc-p...@listserv.ieee.org [mailto:owner-emc-p...@listserv.ieee.org] On Behalf Of Ken Javor Sent: Thursday, December 02, 2004 8:20 PM To: Ron Pickard Cc: emc-p...@ieee.org Subject: Re: Is one-handed electrical shock possible? My comment is 22 nF is an awful lot of stray capacitance. If I were in my screen room and wearing thin soled shoes standing on grounded metal sheet I could see it, but not in a home environment where there is a large separation between every part of my body and ground. > From: Ron Pickard <rpick...@hypercom.com> > Date: Thu, 2 Dec 2004 17:12:23 -0700 > To: ken.ja...@emccompliance.com > Cc: emc-p...@ieee.org > Subject: Re: Is one-handed electrical shock possible? > > > > > > Hi Ken, > > As with you and Gary and I'm fairly sure with just about everyone else > on this list, I've had some experiences, too. However, I won't share > any of them, but suffice it to say as Gary so eloquently relayed it > "Stupid is as stupid does". You can draw your own pictures. > > IMHO, the main resistive element is not restricted to only resistance. > Think of it more as impedance, with capacitive reactance coming into > play. Actually, if you think about it, a capacitor is a fairly good > insulator with DC voltage applied. But, if the impedance is strictly > capacitive (ignoring resistance) and doing a quick calculation with > 120Vac 60Hz voltage being present and producing a current of 1mA, this > yields a capacitance of about 0.022uF (or > 22nF) with a reactance of > about 115Kohms, which falls in line with your 120Kohm resistance estimate. > > Comments? > > Best regards, > > Ron Pickard > rpick...@hypercom.com > > > > ken.javor@emccomplian > ce.com To: emc-p...@ieee.org > Sent by: cc: > owner-emc-pstc@listse Subject: Re: Is one-handed electrical shock > possible? > rv.ieee.org > > > 12/02/2004 04:24 PM > > > > > There have been a great many anecdotal tales submitted, and I could > add my own hair-raising adventures. I suspect just about anyone > living in the civilized world in the latter half of the 20th or > beginning of the 21st century has at one time or other experienced a one-handed shock. > > So the possibility exists, it is undeniable. What is less clear to > me, and what I believe was the point of the original post, and which > has not been answered at least to my understanding, is how does it happen? > > To my way of looking at it, the resistance/capacitance of the human > body is not an issue; if you place mains potential across the body, > current will flow and damage will ensue. What is interesting is that > the one-handed shock can occur when the body is (again, to my > understanding) ungrounded and potentially speaking, floating. The > last time I got shocked I was doing something very similar to Mr. > McInturff. Having for the third time bought a new (for me) home in > Alabama, I was going through the ritual of rotating the electrical > outlets. For some reason older homes in Alabama have the outlets > installed with the safety ground jack up instead of down. Sometimes > that is inconvenient, so I rotate them. Like Mr. McInturff, I didn't want to throw the breaker and was trying to be careful. > > I was sitting on the floor. The floor is covered with wall-to-wall > carpet, which is likely man-made, say nylon or rayon, a pretty good insulator. > Underneath the carpet is the pad, again insulator. Underneath the pad > is the concrete slab. Probably a conductor at a high enough > potential, but I would expect a pretty good insulator at 120 Vac. > > Well, I pulled a McInturff and got a good buzz. I don't know if it > was surprise or muscular contraction, but my leg shot out and I almost > broke something. > > I think 1 mA is supposed to elicit a "surprise" reaction. Someone on > the list please correct me if I'm wrong. If 1 mA was coursing though > my body, that means that the line-to-ground resistance total was only > 120 kOhms. I can't account for that. > > Comments? > > Ken Javor > > ---------------------------------------------------------------- > 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 emc-p...@ieee.org > > Instructions: > 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: emc-p...@hypercom.com > Scott Douglas emcp...@ptcnh.net > > For policy questions, send mail to: > > Richard Nute: ri...@ieee.org > Jim Bacher: j.bac...@ieee.org > > 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. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: 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: emc-p...@hypercom.com Scott Douglas emcp...@ptcnh.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org 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. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: 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: emc-p...@hypercom.com Scott Douglas emcp...@ptcnh.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
