I read in !emc-pstc that Bailey, Jeff <jbai...@mysst.com> wrote (in <B115DFA26896D511BAB600105AA3493275EA3F@SSTMAIL>) about 'Ground potential differences' on Fri, 11 Oct 2002:
> I am interested >to know what the actual magnitude of ground differences may be from one end >of a plant to another as well as where the numbers come from. It depends on what sort of equipment is present. Some things have very high leakage current, putting a lot of amps in total into ground conductors. Then, in old plants, there may be bad ground wiring that doesn't show up as a fault. >Have they >been calculated or actually measured? Both. Usually after the problem has been discovered by chance. I've measured 9 V over a distance of 20 m, but there are reports of much higher voltages. >If shields are connected directly to >chassis at each node of a network will there be an effect of equalizing the >ground levels through the network or will enough current flow to melt the >shield of the cable? Both are possible. -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk Interested in professional sound reinforcement and distribution? Then go to http://www.isce.org.uk PLEASE do NOT copy news posts to me by E-MAIL! ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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://ieeepstc.mindcruiser.com/ Click on "browse" and then "emc-pstc mailing list"
