Hi Tim:
In my message under the subject of "stray voltage," I said: "For wet conditions, we halve the voltage and the current, which is more-or-less the same as halving the body resistance." You asked: "If you halve both voltage and current is that not 0.25 the original resistance?" With respect to electric shock, voltage and current are independent criteria. For low voltages, there is no current criterion. For low currents, there is no voltage criterion. For wet conditions, a safe voltage must not exceed about half the dry voltage regardless of current. If the voltage exceeds about 15 volts (half the dry voltage), then a safe current (0.25 mA) must not exceed about half the dry current (0.5 mA). Or, one can apply the dry condition current, 0.5 mA, but use a wet body resistance of about 750 ohms, which will yield the same result as a wet condition current, 0.25 mA, and a dry condition body resistance of about 1500 ohms. Best wishes for the holiday season, Rich - 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
