<META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=utf-8">
<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40">
<head>
<meta name=Generator content="Microsoft Word 12 (filtered medium)">
<!--[if !mso]>
<style>
v\:* {behavior:url(#default#VML);}
o\:* {behavior:url(#default#VML);}
w\:* {behavior:url(#default#VML);}
.shape {behavior:url(#default#VML);}
</style>
<![endif]-->
<style>
<!--
/* Font Definitions */
@font-face
{font-family:"Cambria Math";
panose-1:2 4 5 3 5 4 6 3 2 4;}
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
@font-face
{font-family:Tahoma;
panose-1:2 11 6 4 3 5 4 4 2 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0in;
margin-bottom:.0001pt;
font-size:12.0pt;
font-family:"Times New Roman","serif";}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:blue;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{mso-style-priority:99;
color:purple;
text-decoration:underline;}
p
{mso-style-priority:99;
mso-margin-top-alt:auto;
margin-right:0in;
mso-margin-bottom-alt:auto;
margin-left:0in;
font-size:12.0pt;
font-family:"Times New Roman","serif";}
span.EmailStyle20
{mso-style-type:personal-reply;
font-family:"Calibri","sans-serif";
color:#1F497D;}
.MsoChpDefault
{mso-style-type:export-only;
font-size:10.0pt;}
@page Section1
{size:8.5in 11.0in;
margin:1.0in 1.0in 1.0in 1.0in;}
div.Section1
{page:Section1;}
-->
</style>
<!--[if gte mso 9]><xml>
<o:shapedefaults v:ext="edit" spidmax="1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext="edit">
<o:idmap v:ext="edit" data="1" />
</o:shapelayout></xml><![endif]-->
</head>
<body lang=EN-US link=blue vlink=purple>
<div class=Section1>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Hello all,<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>While this may be excellent advice, I think it would be good to
clarify that this may apply primarily to grid tied systems. <o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>In Off Grid systems we have different considerations, such as
(a) we are working with lower voltages and need to limit the size of the wire
and the voltage drop, and (b) there IS protection at the equipment room on the
homeruns from the combiners to the equipment room (assuming the combiners are
at the array) as long as we have individual circuit breakers on the input of
each charge controller.<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Thanks,<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Walt<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Arial","sans-serif";
color:#1F497D'>Walt Ratterman<o:p></o:p></span></b></p>
<p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Arial","sans-serif";
color:#1F497D'>SunEnergy Power International</span></b><b><span
style='font-size:10.0pt;color:#1F497D'><o:p></o:p></span></b></p>
<p class=MsoNormal><b><span style='font-size:10.0pt;color:#1F497D'><o:p> </o:p></span></b></p>
<p class=MsoNormal><span style='font-size:8.0pt;font-family:"Arial","sans-serif";
color:#1F497D'>11 Laurel Lane South Washougal, WA 98671<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:8.0pt;font-family:"Arial","sans-serif";
color:#1F497D'>(360)-837-3680 ▪ fax (360)-837-1315 ▪ Skype
Walt-Mobile<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:8.0pt;font-family:"Arial","sans-serif";
color:#1F497D'><a href="mailto:wratterman@SunEPI.org">wratterman@SunEPI.org</a>
</span><span style='font-size:10.0pt;font-family:"Arial","sans-serif";
color:#1F497D'> </span><span style='font-size:8.0pt;font-family:"Arial","sans-serif";
color:#1F497D'>▪ <a href="http://www.sunepi.org/">www.SunEPI.org</a><o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:8.0pt;font-family:"Arial","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<div>
<div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'>
<p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span
style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>
re-wrenches-bounces@lists.re-wrenches.org
[mailto:re-wrenches-bounces@lists.re-wrenches.org] <b>On Behalf Of </b>Matt
Lafferty<br>
<b>Sent:</b> Sunday, December 20, 2009 4:10 PM<br>
<b>To:</b> 'RE-wrenches'<br>
<b>Subject:</b> Re: [RE-wrenches] DC disconnect placement<o:p></o:p></span></p>
</div>
</div>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";
color:blue'>William,</span><o:p></o:p></p>
<p class=MsoNormal> <o:p></o:p></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";
color:blue'>Put the inverters at the array. Run the AC underground.
If the AC feeder gets dug up by some rowdy backhoe operator in
the future, the breaker (or series of breakers) will open, de-energizing the
circuit immediately (and maybe the main to the residence at the same time).</span><o:p></o:p></p>
<p class=MsoNormal> <o:p></o:p></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";
color:blue'>If you are dead-set on putting the inverters in the pump shed, put
any combiner(s) at the inverters. This affords the maximum overcurrent
protection for the underground feeders. Install DC disconnecting means in each string
before leaving the array if you go this route.</span><o:p></o:p></p>
<p class=MsoNormal> <o:p></o:p></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";
color:blue'>For maximum protection of conductors and to minimize arc hazards,
The SAFEST location for a combiner is ALWAYS at the inverter. All
conductors on the inverter (load) side of a fused combiner are unprotected by
anything other than their ampacity rating. If a fault occurs on the load side
of a combiner, it will burn until it clears or welds to a dead short. </span><o:p></o:p></p>
<p class=MsoNormal> <o:p></o:p></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";
color:blue'>Cheers,</span><o:p></o:p></p>
<p class=MsoNormal> <o:p></o:p></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";
color:blue'>Matt Lafferty</span><o:p></o:p></p>
<div>
<p class=MsoNormal><br>
<o:p></o:p></p>
</div>
<div class=MsoNormal align=center style='text-align:center'>
<hr size=2 width="100%" align=center>
</div>
<p class=MsoNormal style='margin-bottom:12.0pt'><b><span style='font-size:10.0pt;
font-family:"Tahoma","sans-serif"'>From:</span></b><span style='font-size:10.0pt;
font-family:"Tahoma","sans-serif"'> re-wrenches-bounces@lists.re-wrenches.org
[mailto:re-wrenches-bounces@lists.re-wrenches.org] <b>On Behalf Of </b>William
Miller<br>
<b>Sent:</b> Sunday, December 20, 2009 11:02 AM<br>
<b>To:</b> RE-wrenches<br>
<b>Subject:</b> [RE-wrenches] DC disconnect placement</span><o:p></o:p></p>
<p class=MsoNormal>Friends:<br>
<br>
I am embarking on a 10 Kw ground mount grid-tie installation. The client
prepared for this installation some time ago by stubbing a PVC conduit
underground towards the future location of the PV array. Prior to
beginning this job, an excavation contractor intercepted the empty conduit with
a backhoe.<br>
<br>
No harm was done because this conduit was empty. Had this conduit been
filled with PV feeders, it would have been very necessary to be able to
disconnect the PV arrays, both for safety and to prevent a brush fire in our
very dry climate.<br>
<br>
The inverters will be located in a pump house about 130 feet from the PV
arrays. I would not normally put disconnects at the array and they are
not required. This scenario, however, has caused me to reconsider.
The design now calls for a disconnect at each row of modules. I feel that
it would not be prudent to delete this important safety item.<br>
<br>
I wish there were a better selection of compact, low profile disconnects
suitable for a roof-top installation. I have put external handle
disconnects on roof but they look terrible. I may specify touch-safe fuse
holders inside of a Sola Deck for future comp roof jobs. I am not sure
what we will do with tile roofs.<br>
<br>
It seems to me that every source of power should have a means of disconnection
as close to the source as possible. This is just common sense.<br>
<br>
William Miller<br>
<br>
<br>
<o:p></o:p></p>
<p><u>Please note new e-mail address and domain:<br>
<br>
</u>William Miller <br>
Miller Solar<br>
Voice :805-438-5600<br>
email: william@millersolar.com<br>
<a href="http://millersolar.com/">http://millersolar.com<br>
</a>License No. C-10-773985<o:p></o:p></p>
</div>
</body>
</html>