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Peter,<div>i've been having the same concern running thru my head recently, as i've done this myself, and have compensated by now using a green jacketed bond (ground) wire for rail and module bonding. (fyi-bonding is the CEC term for inter-connecting all metallic parts of an electrical system, i.e. frames, rails)</div><div>I just strip the jacket at the lugs and use nolox on all connections.</div><div><br></div><div>I have not yet seen any issues with corrosion when bare copper has been supported against aluminum (frames or rails), but i am watching for it. </div><div><br></div><div>I am also curious if anyone else has encountered this.... and,</div><div>-to what extent (i've seen mod frame/lug 'reduced to white powder' photos, but what about rail damage?</div><div>-age of install when corrosion was first noticed</div><div><br></div><div>Question(s): </div><div>What triggers galvanic <u>corrosion</u> to take place? ...is it unavoidable if there are dissimilar metals in contact?</div><div>Does there need to be current leaking thru the dissimilar metals (connection points) for the reaction to start?</div><div><br></div><div>benn<br><br><span class="ecxecxecxecxEC_Apple-style-span" style="color:rgb(0, 32, 96)"><font class="ecxApple-style-span" face="'Franklin Gothic Medium'">DayStar Renewable Energy Inc. </font></span><div><div><font class="ecxApple-style-span" face="'Franklin Gothic Medium'">benn@daystarsolar.ca</font></div><div><font class="ecxApple-style-span" face="'Franklin Gothic Medium'">780-906-7807 </font></div><div><font class="ecxApple-style-span" face="'Franklin Gothic Medium'">HAVE A SUNNY DAY
</font></div><div><br></div></div><br><br><br><br>> From: peter.parrish@calsolareng.com<br>> To: re-wrenches@lists.re-wrenches.org<br>> Date: Fri, 14 Jan 2011 07:36:22 -0800<br>> Subject: [RE-wrenches] Incompatible Metals<br>> <br>> One of my students who is currently responsible for standing for inspection<br>> at their company encountered a inspector who made an interesting point about<br>> incompatible metals (i.e. copper and anodized aluminum).<br>> <br>> The PV system in question used outdoor rated lay-in lugs to bond the rails<br>> to bare copper wire (so far so good). The ground wire was then zip-tied to<br>> the rail to carry it to the point where it entered a junction box along with<br>> the rest of the PV conductors.<br>> <br>> The inspector was concerned with the fact that the bare copper was in<br>> contact with the aluminum rails and that this might cause galvanic corrosion<br>> and subsequent failure of the grounding.<br>> <br>> I have never encountered this issue before and I wonder if anyone else has<br>> and what was the outcome.<br>> <br>> As an aside: I do know that 10 AWG and 12 AWG solid bare copper wire can be<br>> purchased "pre-tinned" (maybe not tin per se, but coated). We did so by<br>> mistake. We used it up, but not before one inspector questioned its use for<br>> the purpose of grounding our system. We showed him the UL label on the spool<br>> and scraped off the coating to expose the copper core and that satisfied<br>> him. To this day I don't know if the use of this wire for grounding was<br>> among its intended purposes.<br>> <br>> - Peter<br>> <br>> Peter T. Parrish, Ph.D., President<br>> California Solar Engineering, Inc.<br>> 820 Cynthia Ave., Los Angeles, CA 90065<br>> CA Lic. 854779, NABCEP Cert. 031806-26<br>> peter.parrish@calsolareng.com <br>> Ph 323-258-8883, Mobile 323-839-6108, Fax 323-258-8885<br>> <br>> <br>> _______________________________________________<br>> List sponsored by Home Power magazine<br>> <br>> List Address: RE-wrenches@lists.re-wrenches.org<br>> <br>> Options & settings:<br>> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org<br>> <br>> List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org<br>> <br>> List rules & etiquette:<br>> www.re-wrenches.org/etiquette.htm<br>> <br>> Check out participant bios:<br>> www.members.re-wrenches.org<br>> <br></div> </body>
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