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-bounces@lists.re-wrenches.org [mailto:
re-wrenches-bounces@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 ---

