Nik, Looks to me like there may be a major bird flyway between the dormers directly over the bottom row of modules. A google search seems to confirm a correllation between between bird droppings and copper roof staining. I agree with August, this doesn't seem to be an issue caused by dissimilar metal electrolysis. It is interesting that there are "hot spots" below the long sides of the module frames. How are the modules grounded, WEEBS or lugs and bare copper?
I would recommend installing devices to prevent the birds from roosting in the dormers and continued monitoring to see if things stabilize. Dick Ratico Solarwind Electric --- You wrote: Hi Nik, This is an interesting one. What is going on along the bottom edge of the modules? Is that corrosion or lichen or bird poop remnants? The racking and sides of the modules look fine. I suppose moisture might be collecting along the bottom module lip and something is happening to the black anodizing there. It looks like you have a piece of rubber separating the brass S5 clamp from the L-foot? The only thing that I can think of that might be dielectric related might be making sure there is a good bond between the module frame, racking, and roof but that doesn't really seem to be the issue here. Looks like a nice building! Best, August *August Goers* Luminalt Energy Corporation o: 415.641.4000 m: 415.559.1525 *From:* re-wrenches-boun...@lists.re-wrenches.org [mailto: re-wrenches-boun...@lists.re-wrenches.org] *On Behalf Of *Nik Ponzio, Building Energy *Sent:* Monday, September 16, 2013 2:10 PM *To:* RE-wrenches *Subject:* [RE-wrenches] copper roof Dear Wrenches, We installed a PV system on a copper roof several years ago. We used brass S5!-U clamps on standing seam and aluminum racking. We are now noticing some discoloration at the drip-line below the modules. See photos here: https://picasaweb.google.com/109634809794570027207/CopperRoof?authuser=0&authkey =Gv1sRgCMv8n6rCl8e8Sw&feat=directlink There is also a fair amount of discoloration from bird droppings but that doesn't seem to be the cause of the spots under the modules. Does any know what's happening here, whether to be concerned about corrosion, and how to prevent this in the future? --- end of quote --- _______________________________________________ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
