I read in !emc-pstc that [email protected] wrote (in <2DF7C54A75B [email protected]>) about 'electrochemical potentials' on Wed, 15 Oct 2003:
>I am reviewing some dissimilar material combinations in an earthing >path. I have reviewed a lot data available on-line and in a few >reference texts. I would now like to better understand the origins of >Table J.1 in IEC60950. > >Does anyone know where the data on which Table J.1 is based originated? I didn't receive the original message. I found, several years ago, an error in the table and at that stage tried to find out where it came from, without success. > >Was it a reference standard or data from an industry association? >Something else? It doesn't seem to come from another standard. > >I am finding Table J.1 might be useful as a reference, but little else. >The types of alloys referenced can have electrochemical potential >differences relative to one another that vary 10% or more from the >values shown in the table. > >I'd appreciate any input you might have. It's not actually much use at all. These potentials give an indication of the probability of electrolytic corrosion under *laboratory* conditions, with no contaminants. They don't give reliable indications in the real world, where contaminant ions, such as chloride, sulfide and sulfate, occur. Having said that, avoiding combinations that involve high potentials minimises the probability of serious short-term corrosion, but by no means guarantees acceptable results. -- 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: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: [email protected] Dave Heald: [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
