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 [email protected] ken.javor@emccomplian ce.com To: [email protected] 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 [email protected] 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: [email protected] Scott Douglas [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. 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/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] Scott Douglas [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
