On Monday, February 13, 2012 08:17:33 PM Roland Jollivet did opine: > But.. you can take almost any piece aluminium lying around (not > anodised), lightly touch it with the blunt rounded side of two > crocodile clips, and you'll measure a few milliohms. What happened to > the oxide layer? It's so thin that a few mN of pressure tore through > it. > > Regards > Roland
Chuckle. :) Now do this, Roland, clip two small clip leads to that piece of alu sheet, and measure the ohms, likely very low, and write it on the alu with the usual magic marker. Carefully set that sheet, clips and all, up on a shelf for 6 months, then without disturbing those clips, measure from the other ends of those clip leads 6 months later. Those clips teeth do not have what it takes to make a "gas tight" connection, and sitting there clipped without being disturbed will demonstrate why I inspect the wiring in any building I contemplate sleeping in for 3 nights in a row. If its a house I'm thinking about buying, and I find alu wire anyplace in the service, no deal unless the seller wants to replace it with copper, on his dime, before I sign on the dotted line. I will not buy a time bomb. An alu related and caused fire occurred in the service box, 8 feet from the bed I was sleeping in back in the '70's, but I recognized the sound, and had what it took to go rip the meter out of its socket and fix it temporarily, at 2am in a 20 below Nebraska night. The next day I "borrowed" a foot of copper cable from the tv station I was in charge of, and replaced that foot of alu range cable some idiot who probably had an electricians card in his wallet put in when that old farmhouse was wired 15 years back up the log. That could, had I not awoke from the buzzing, have been a fatal fire for the whole family of 11 that night, and its a lesson not easily forgotten. 11? Yeah, her 3, my 3, and our 3 plus the two of us. Technically, ripping the seal off the meter is a felony in Nebraska, so when I called Ron, the super at Wayne County Public Power & asked him to come by and put a new seal on my homes meter after doing the fix the next day, Ron was understandably curious as to the reason he had to record a new seal number on my meter. But, since the tv station I was then in charge of was his largest customer by a factor of 4 or 5 (30 kw UHF transmitters in those days were klystrons and used around 225 kw/h during the broadcast day), we were already good friends so nothing more was said. Hey Ed, here's another "war story" for your "larval engineer". ;-) Cheers, Gene -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) My web page: <http://coyoteden.dyndns-free.com:85/gene> I am the mother of all things, and all things should wear a sweater. ------------------------------------------------------------------------------ Keep Your Developer Skills Current with LearnDevNow! The most comprehensive online learning library for Microsoft developers is just $99.99! Visual Studio, SharePoint, SQL - plus HTML5, CSS3, MVC3, Metro Style Apps, more. Free future releases when you subscribe now! http://p.sf.net/sfu/learndevnow-d2d _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
