[TowerTalk] Power ground

[Dubovsky, George]

Interesting that "silver solder" is rated to a higher temp than compression fittings. Silver solder is really brazing, by definition. For instance Harris "StaySilv15" (a common "silphos" braze w/15% silver, often used in refrigeration tubing joints), has a solidus temp of 1190 F (643 C); it's liquidus point (melting point) is a couple hundred higher. A very common silver solder, Harris StaySilv56 (56% silver), has its solidus temp 40 degrees F lower; it is often used to join cast iron and steel together, where you don't want to melt the parent metal. It is *definitely not* soft solder. 

I'm with K8RI - a brazed connection is not an inferior electrical connection when compared with the usual compression fitting. I wonder if the term "compression", as used by the IEEE, includes the Nicopress-types, usually installed with a big-ass, hydraulic crimper. I always thought those would be excellect connections, mechanically and electrically.

73,

geo - n4ua

> -----Original Message-----
> From: Wilson Lui [mailto:wilsonlui at atitec.com]
> Sent: Wednesday, May 26, 2004 2:30 PM
> To: 'Tower (K8RI)'; TowerTalk at contesting.com
> Subject: RE: [TowerTalk] Power ground
> 
> 
> Here's a little clarification for the different types of 
> connections. IEEE
> Std. 80 recognizes the following maximum limits for the 
> different types of
> connections. These limits are measured in Celsius (C), if 
> exceeded, the
> connections may fail. 
> 
> Copper Wire (no connector) - 1083 (C)
> Exothermic - 1083 (C)
> Silver Solder - 450 (C)
> Compression Fitting - 350 (C)
> Screw Type - 250 (C)
> Solder (50/50) - 220 (C)
> Wires Twisted Together - 100 (C)
> 
> 
> Wilson Lui
> ATI Tectoniks
> wilsonlui at atitec.com
> 
> 
> Please visit our website at http://www.atitec.com for more 
> information.
> 
> -----Original Message-----
> From: Tower (K8RI) [mailto:tower at rogerhalstead.com] 
> Sent: Wednesday, May 26, 2004 10:57 AM
> To: K7LXC at aol.com; wilsonlui at atitec.com; davidw at copper.net;
> TowerTalk at contesting.com
> Subject: Re: [TowerTalk] Power ground
> 
> I've been following this for a while and keep seeing 
> reference to "brazed"
> water pipes.
> I've never seen a brazed joint in water pipes. Soldered, but 
> never brazed.
> 
> The temperature for brazing is much higher than soldering and would be
> enough to show some serious oxidation on the copper.  Brazing 
> would require
> the copper to be at a "cherry red" heat to get the stuff to 
> melt.  In most
> homes the amount of heat required would cause charring on any 
> wood near the
> joint.
> 
> It may not be permitted, but I'd trust a good brazed joint 
> any day over a
> compression fitting that can corrode.  I've had compression fittings
> completely lose contact with ground rods.
> 
> 
> Roger Halstead (K8RI, EN73 & ARRL Life Member)
> N833R, World's Oldest Debonair (S# CD-2)
> www.rogerhalstead.com
> 
> 
> > In a message dated 5/26/04 10:17:54 AM Pacific Daylight Time,
> > wilsonlui at atitec.com writes:
> >
> > > However using
> > >  brazed water pipes is not recommended. The brazed 
> connections represent
> a
> > >  seriously weak electrical joint and may fail prematurely 
> under thermal
> > >  stress of high currents.
> >
> >     Yessireebob. The only NEC ground connections allowed 
> are compression
> and
> > exothermic (i.e. Cadweld).
> >
> > Cheers,
> > Steve     K7LXC
> > TOWER TECH -
> > Professional tower services for commercial and amateur
> > 888-833-3104
> >
> > _______________________________________________
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> 
> 
> 
> 
> _______________________________________________
> 
> See: http://www.mscomputer.com  for "Self Supporting Towers", 
> "Wireless Weather Stations", and lot's more.  Call Toll Free, 
> 1-800-333-9041 with any questions and ask for Sherman, W2FLA.
> 
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