<html><head><style type="text/css"><!-- DIV {margin:0px;} --></style></head><body><div style="font-family:times new roman, new york, times, serif;font-size:12pt"><DIV>Good wire splices and connections require good mechanical connections first. Some people like to solder the wire after they make the mechanical connection, but solder can hide a bad mechanical connection and provide a place for corrosion to form.</DIV>
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<DIV>Joel Davidson<BR></DIV>
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<B><SPAN style="FONT-WEIGHT: bold">From:</SPAN></B> The Office of Tom Duffy <tom@thesolar.biz><BR><B><SPAN style="FONT-WEIGHT: bold">To:</SPAN></B> RE-wrenches <re-wrenches@lists.re-wrenches.org><BR><B><SPAN style="FONT-WEIGHT: bold">Sent:</SPAN></B> Wednesday, December 3, 2008 9:48:28 AM<BR><B><SPAN style="FONT-WEIGHT: bold">Subject:</SPAN></B> Re: [RE-wrenches] Soldering electrical conductors<BR></FONT><BR>
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<DIV dir=ltr align=left><FONT face=Arial color=#0000ff size=2><SPAN class=156073117-03122008>About 28 years ago I read a study, by either Niehoff or Prestolite, on the pros and cons of soldering or crimping, heavy duty starter cables, for over the road trucks. </SPAN></FONT></DIV>
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<DIV dir=ltr align=left><FONT face=Arial color=#0000ff size=2><SPAN class=156073117-03122008>The finding was, that a properly crimped lug made a solid (molecular) connection while solder did not make as good a connection because solder was not as good a conductor as copper. They concluded that the crimped connection carried more amperage and did so over the long haul. </SPAN></FONT></DIV>
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<DIV dir=ltr align=left><FONT face=Arial color=#0000ff size=2><SPAN class=156073117-03122008>We use an air over hydraulic crimper on all our cables with a hydraulic gauge reading of 10,000 lbs PSI. I have done a pull test with this connection by pulling a truck behind another with this connection</SPAN></FONT></DIV>
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<DIV dir=ltr align=left><FONT face=Arial color=#0000ff size=2><SPAN class=156073117-03122008>Tom Duffy</SPAN></FONT></DIV>
<DIV dir=ltr align=left><FONT face=Arial color=#0000ff size=2><SPAN class=156073117-03122008>The Solar Biz</SPAN></FONT></DIV></BLOCKQUOTE>
<DIV><FONT face=Tahoma><FONT size=2><STRONG>From:</STRONG> re-wrenches-bounces@lists.re-wrenches.org [mailto:re-wrenches-bounces@lists.re-wrenches.org] <B>On Behalf Of </B>North Texas Renewable Energy Inc<BR><B>Sent:</B> Wednesday, December 03, 2008 10:08 AM<BR><B>To:</B> RE Wrenches<BR><B>Subject:</B> [RE-wrenches] Soldering electrical conductors<BR></FONT></FONT><BR></DIV>
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<DIV><FONT face=Arial>Wrenches</FONT></DIV>
<DIV><FONT face=Arial>Over the years I have heard almost nothing about soldering of electrical connections in PV circuits, AC or DC. The only reference I recall is from the recommendation that one should crimp AND solder larger compression fittings to assure a permanent connection. There were references to factory made battery cable crimps not holding after installation and during the final "pull-test". </FONT></DIV>
<DIV><FONT face=Arial>I can't find any reference to the practice in the NEC, either pro or con. It seems that any technique so susceptible to poor results would be at least addressed. </FONT></DIV>
<DIV><FONT face=Arial>The reason I want to definitively address this practice, by the Wrenches community, is this.</FONT></DIV>
<DIV><FONT face=Arial>A group of PV industry specialists were invited to help develop a curriculum for a state funded technical college with 4 separate campuses. The Waco Campus, with the fuel cell and wind degree programs, is now creating a solar installer technician degree program. </FONT></DIV>
<DIV><FONT face=Arial>A group of experts spent two days picking our brains to help create an overview plus detailed duties, tasks and the separate steps involved in the design/installation process.</FONT></DIV>
<DIV><FONT face=Arial>So now that the initial draft is finished we are asked to critique it. </FONT><FONT face=Arial>One of the "General Knowledge" items is <U>soldering techniques</U>. </FONT></DIV>
<DIV><FONT face=Arial>I need to mention that the degree will cover both PV and thermal installs. Of course some soldering is necessary in the thermal installation process, less since the introduction of compression connections, but I'm interested in addressing the electrical side. </FONT></DIV>
<DIV><FONT face=Arial>If any negative long-term effects from solder joints have been discovered I would like to hear about them. If they seem serious enough, I would consider recommending that the staff include a clarification that electrical soldering should be avoided. </FONT><FONT face=Arial>If the long-term effect is negligible, it is still possible to do an electrically poor job even using top quality equipment. </FONT></DIV>
<DIV><FONT face=Arial>I'll defer to the collective knowledge of this organization.</FONT></DIV>
<DIV><FONT face=Arial>Thanks as always</FONT></DIV>
<DIV><FONT face=Arial>Jim Duncan<BR>North Texas Renewable Energy Inc<BR>817.917.0527<BR><A href="mailto:ntrei@earthlink.net" target=_blank rel=nofollow ymailto="mailto:ntrei@earthlink.net">ntrei@earthlink.net</A><BR><A href="http://www.ntrei.com/" target=_blank rel=nofollow>www.ntrei.com</A> </FONT></DIV></DIV></DIV></div></body></html>