In message <of2653a36e.b3b5d745-on652576a3.003da9dd-652576a3.003e4...@scmmicro.co.in >, dated Wed, 6 Jan 2010, kbalasubraman...@scmmicro.co.in writes:
> In case the device enclosure is non conducting, then where to connect >the USB cable shield conductor? Should we isolate the DC negative (the >digital ground of the circuitry) of the USB 5 volts power from the USB >cable shield? No, NEVER isolate a shield. Remember the 'water tanks' analogy. If there is no conductive enclosure, and no substantial metalwork inside the enclosure, you have to experiment to find the place to connect the shield to 'ground' that causes the least trouble. I advocate not using that construction if at all possible, and certainly not for any product produced in small numbers, where the cost of extensive testing and failing is likely to be disproportionate to the cost of providing a conducting enclosure. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK I should be disillusioned, but it's not worth the effort. - 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 <emc-p...@ieee.org> All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. 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 <emcp...@socal.rr.com> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher: <j.bac...@ieee.org> David Heald: <dhe...@gmail.com>
