Wrenches,
Thanks to the wind-sun folks for sharing this fire story. There is a lot of conjecture in the thread, and much of it is wrong. With all due respect to Solar-Guppy, PV module encapsulant, EVA, is highly flammable, and tedlar will burn as well. The good news is that there is not a lot of fuel in the module. However, coupled with other fuels, there may be a problem. John Wiles and UL are advocating arc-fault detectors for PV arrays. It's pretty clear that this fire would have started with an arcing fault. My first impression is that these are not listed modules and therefore have not been tested for maximum voltage. The maximum voltage tests are very stringent and just from a picture of the construction, these modules would be very unlikely to pass the test. Many comments were made as to the substandard structure-that is obvious. Just because several people on the list have not seen this happen before, poorly manufactured modules can, and will do this. Even some of the best manufacturers in the world have screwed up on their construction and had fires. Without a NRTL (Nationally Recognized Testing Lab) involved in the process, there is no basic understanding of the safety of a product. Anyone who entertains the idea of installing non-listed modules at higher voltages, as may be the case with this fire, should just post these pictures on their office wall. There is no way that the money this installer saved by buying substandard product could be worth this danger. On Friday UL will be testing to see if PV modules can reduce the fire rating of class A roofing. I don't think it will, but let's hope not. These pictures will be inspiration for the day's testing. Bill. From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of William Miller Sent: Wednesday, February 11, 2009 12:57 AM To: RE-wrenches Subject: Re: [RE-wrenches] Panel Fire Dear Wind-Sun: The incident described on your forum is very Interesting and scary. It is impossible to make any definitive conclusions from the vague information provided, but here are a few things that got my attention: --If I could detect, from the before photos provided, a first rate installation, I would suspect defective modules. The before photo shows some very non-standard, low quality racking, obviously slapped together from hardware store angle stock. The angles are installed across the roof pitch, catching leaves and rain water. This makes me wonder how poorly the rest of the wiring could have been and suspect that poor workmanship may be to blame. --The homeowner claims the modules are un-stickered (no specifications, manufacturer or listing). The entire package begins to appear to be a real bargain basement system. The fact that this system caught fire seems to make sense. We replaced a module today that had heat damaged connection points. It appears one of my employees did not tighten a screw terminal on an old style module and the connections got hot. The J-box cover was melted. This module had been removed and reinstalled for a re-roof. I know stainless fasteners are not conducive to repeated loosening and re-tightening, so maybe the connector screw was galled and could not be tightened. properly. I have often predicted it is only a matter of time until our industry kills someone. My bet is on electrocution of a minor due to abraded PV cables. Maybe I'm wrong and it will be in a house fire. All I can say is that I am doing everything in my power to prevent it from being on one of my jobs and to spread the gospel of protected wiring. William Miller At 10:42 PM 2/10/2009, you wrote: In view of the recent discussion here about fires and PV systems, you might all want to take a look at this post that someone just posted on our forum http://www.wind-sun.com/ForumVB/showthread.php?t=4524 I never heard of this happening before. ............................................................................ ...................... Northern Arizona Wind & Sun - Electricity From The Sun Solar Discussion Forum: http://www.wind-sun.com/ForumVB/ ............................................................................ ......................
_______________________________________________ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options & 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