In message <9d04b979323dcd428297dda95108893e037c8...@bb-corp-ex2.corp.cubic.cub>, dated Thu, 24 Dec 2009, "Price, Edward" <[email protected]> writes:
>star washers are not the best choice. Although the tiny points of the >star washer probably have sufficient contact pressure to maintain a >gas-tight contact (and not oxidize over a long time), those same tiny >points do not provide a large conductive path for a fault current. I don't think that's true. When the bolt is tightened, the points gouge into the base metal and deform it. The contact area is small, but not point-like. When you consider what currents the bond wires in power semiconductors carry, it changes your view on conductor sizes and currents. Cables are dimensioned taking into account long life of the insulation, low voltage drop and elevated ambient temperatures. If in doubt, zap some anchorages using star washers with 25 A or more. I think you will find they are quite OK, provided the bolt was tightened sufficiently. (Tighten until the bolt breaks and back off two whole turns.)(;-) -- 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 Help stamp out intolerance! - 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 <[email protected]> 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 <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher: <[email protected]> David Heald: <[email protected]>
