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<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Wrenches,<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>It has been a while since I have seen this
subject and I was wondering if there has been more experience in the field with
using either EPDM or products such as <a
href="http://www.eternabond.com/DoubleStick-p/cr-ds.htm">http://www.eternabond.com/DoubleStick-p/cr-ds.htm</a>
for sealing L-feet or stand-offs directly to metal roofing. . .<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Seems to make sense to directly seal off
the one or two holes for that lags rather than placing a boot over it and
drilling 20 screws around the Otey. The only weakness I could see would
be the seal directly over the lags, but I think this could be cured with a
dollop of silicone or other EPDM safe caulk in and on top of the hole.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>My main worry is the compression of the
material over time, which may compromise the bond/seal.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Has anyone successfully used the
Eternabond—looks like it could be a good solution.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<div>
<p class=MsoAutoSig><font size=2 color=navy face="Comic Sans MS"><span
style='font-size:10.0pt;font-family:"Comic Sans MS";color:navy'>Best regards,<o:p></o:p></span></font></p>
<p class=MsoAutoSig><font size=2 color=navy face="Comic Sans MS"><span
style='font-size:10.0pt;font-family:"Comic Sans MS";color:navy'><o:p> </o:p></span></font></p>
<p class=MsoAutoSig><font size=2 color=navy face="Comic Sans MS"><span
style='font-size:10.0pt;font-family:"Comic Sans MS";color:navy'>Mark </span></font><font
size=2 color=navy face="Comic Sans MS"><span style='font-size:10.0pt;
font-family:"Comic Sans MS";color:navy'>Dickson,</span></font><font color=navy><span
style='color:navy'><o:p></o:p></span></font></p>
<p class=MsoAutoSig><font size=2 color=navy face=ArialMT><span
style='font-size:10.0pt;font-family:ArialMT;color:navy'>NABCEP Certified Solar
PV Installer ™<o:p></o:p></span></font></p>
<p class=MsoAutoSig><font size=2 color=navy face="Comic Sans MS"><span
style='font-size:10.0pt;font-family:"Comic Sans MS";color:navy'>Oasis Montana
Inc.<o:p></o:p></span></font></p>
</div>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
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<p class=MsoNormal><b><font size=2 face=Tahoma><span style='font-size:10.0pt;
font-family:Tahoma;font-weight:bold'>From:</span></font></b><font size=2
face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma'> re-wrenches-bounces@lists.re-wrenches.org
[mailto:re-wrenches-bounces@lists.re-wrenches.org] <b><span style='font-weight:
bold'>On Behalf Of </span></b>William Miller<br>
<b><span style='font-weight:bold'>Sent:</span></b> Sunday, November 14, 2010
10:36 PM<br>
<b><span style='font-weight:bold'>To:</span></b> RE-wrenches<br>
<b><span style='font-weight:bold'>Subject:</span></b> Re: [RE-wrenches] Head
Spinning..(Con) fused.</span></font><o:p></o:p></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>Eric:<br>
<br>
Thanks for the research. I confess that I commented on an inverter system
I knew little about. My thanks to Darryl for keeping me honest, and for
the kind words. I had assumed that all modern inverters are certified to
prevent back feed, but this needs to be checked for each new inverter.<br>
<br>
I'm not sure the language below is the same as an independent verification that
back feed will not occur. You may need to ask your AHJ what they will
accept.<br>
<br>
The limit on allowable back current is the fuse sizing specified by the module
manufacturer. This relates to how much fault current the internal module
wiring can handle before it fails (and possibly catches fire).<br>
<br>
Humbly,<br>
<br>
William Miller<br>
<br>
<br>
<br>
<br>
<br>
At 07:42 PM 11/14/2010, you wrote:<br>
<br>
<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>Thanks William and Daryl,<br>
<br>
Here is Auroras backfeed stipulation from the installation manual:<br>
<br>
"Installation and Operator’s Manual Page 98 of 108<br>
<br>
(PVI-3.0/3.6/4.2-OUTD-x-US Rev: 2.1)<br>
<br>
<b><span style='font-weight:bold'>8.5 Input Source Backfeed Current</span></b><br>
<br>
PVI-4.2(3.6, 3.0)-OUTD-x-US Grid Tied Inverters are provided with two separate
and<br>
consecutive power stages:<br>
<br>
• Booster Stage (DC-DC converter) connected to DC Input Terminals.<br>
• Inverter Stage (DC-AC converter) connected to AC Output Grid Terminals.<br>
<br>
The Booster Stage is provided with forward diodes that allows the current
(power)<br>
flow only from DC Input terminals towards Inverter (Output) Stage.<br>
In case of any fault on Inverter Stage, these diodes avoid any back-feed
current<br>
phenomena towards input terminals.<br>
<br>
In case of fault of the forward diode, the corresponding booster MOSfet goes<br>
immediately and permanently in short circuit state and it avoids any current<br>
propagation form output to input terminals.<br>
<br>
Abnormal Fault tests conducted during UL1741 qualification show also that these
type<br>
of faults produce the opening of internal grid disconnect relays and cause the
external<br>
AC CB protection devices to trip, preventing any power flow from the grid.<br>
<br>
In conclusion for PVI-4.2(3.6, 3.0)-OUTD-x-US-y models it is not possible to
have<br>
any single fault responsible of Input source back-feed current flow. For these
models<br>
the Back-feed current into DC Source is negligible."<br>
<br>
According to this, the inverter will not backfeed even under most fault
conditions. My biggest concern is the four independent strings shorting
together somehow. I guess technically 4 strings of 8A for a total of 32A
doesn't exceed the ampacity of 10AWG XHHW-2....until you derate it for roof
temps. <br>
<br>
So whats the consensus?<br>
<br>
-- <br>
Eric Thomas<br>
Solar Epiphany LLC<br>
(206) 919-3014<br>
<a href="http://www.solarepiphany.com">www.solarepiphany.com</a><br>
<br>
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<p></x-sigsep><u><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><x-sigsep>Please note new e-mail address and domain:<br>
<br>
</span></font></u>William Miller <br>
Miller Solar<br>
Voice :805-438-5600<br>
email: william@millersolar.com<br>
<a href="http://millersolar.com/" eudora=autourl>http://millersolar.com<br>
</a>License No. C-10-773985<o:p></o:p></p>
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