[RE-wrenches] Panel Fire

Bill Brooks billbrooks7 at yahoo.com
Wed Feb 11 09:32:54 PST 2009


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

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Northern Arizona Wind & Sun - Electricity From The Sun
Solar Discussion Forum: http://www.wind-sun.com/ForumVB/
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