<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 http-equiv=Content-Type content="text/html; charset=us-ascii"><meta name=Generator content="Microsoft Word 14 (filtered medium)"><style><!--
/* Font Definitions */
@font-face
{font-family:Wingdings;
panose-1:5 0 0 0 0 0 0 0 0 0;}
@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;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0in;
margin-bottom:.0001pt;
font-size:11.0pt;
font-family:"Calibri","sans-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;}
pre
{mso-style-priority:99;
mso-style-link:"HTML Preformatted Char";
margin:0in;
margin-bottom:.0001pt;
font-size:10.0pt;
font-family:"Courier New";}
span.EmailStyle17
{mso-style-type:personal-compose;
font-family:"Calibri","sans-serif";
color:windowtext;}
span.HTMLPreformattedChar
{mso-style-name:"HTML Preformatted Char";
mso-style-priority:99;
mso-style-link:"HTML Preformatted";
font-family:"Courier New";}
.MsoChpDefault
{mso-style-type:export-only;
font-family:"Calibri","sans-serif";}
@page WordSection1
{size:8.5in 11.0in;
margin:1.0in 1.0in 1.0in 1.0in;}
div.WordSection1
{page:WordSection1;}
/* List Definitions */
@list l0
{mso-list-id:442773163;
mso-list-template-ids:615267518;}
@list l0:level1
{mso-level-number-format:bullet;
mso-level-text:\F0B7;
mso-level-tab-stop:.5in;
mso-level-number-position:left;
text-indent:-.25in;
mso-ansi-font-size:10.0pt;
font-family:Symbol;}
@list l0:level2
{mso-level-number-format:bullet;
mso-level-text:o;
mso-level-tab-stop:1.0in;
mso-level-number-position:left;
text-indent:-.25in;
mso-ansi-font-size:10.0pt;
font-family:"Courier New";
mso-bidi-font-family:"Times New Roman";}
@list l0:level3
{mso-level-number-format:bullet;
mso-level-text:\F0A7;
mso-level-tab-stop:1.5in;
mso-level-number-position:left;
text-indent:-.25in;
mso-ansi-font-size:10.0pt;
font-family:Wingdings;}
@list l0:level4
{mso-level-number-format:bullet;
mso-level-text:\F0A7;
mso-level-tab-stop:2.0in;
mso-level-number-position:left;
text-indent:-.25in;
mso-ansi-font-size:10.0pt;
font-family:Wingdings;}
@list l0:level5
{mso-level-number-format:bullet;
mso-level-text:\F0A7;
mso-level-tab-stop:2.5in;
mso-level-number-position:left;
text-indent:-.25in;
mso-ansi-font-size:10.0pt;
font-family:Wingdings;}
@list l0:level6
{mso-level-number-format:bullet;
mso-level-text:\F0A7;
mso-level-tab-stop:3.0in;
mso-level-number-position:left;
text-indent:-.25in;
mso-ansi-font-size:10.0pt;
font-family:Wingdings;}
@list l0:level7
{mso-level-number-format:bullet;
mso-level-text:\F0A7;
mso-level-tab-stop:3.5in;
mso-level-number-position:left;
text-indent:-.25in;
mso-ansi-font-size:10.0pt;
font-family:Wingdings;}
@list l0:level8
{mso-level-number-format:bullet;
mso-level-text:\F0A7;
mso-level-tab-stop:4.0in;
mso-level-number-position:left;
text-indent:-.25in;
mso-ansi-font-size:10.0pt;
font-family:Wingdings;}
@list l0:level9
{mso-level-number-format:bullet;
mso-level-text:\F0A7;
mso-level-tab-stop:4.5in;
mso-level-number-position:left;
text-indent:-.25in;
mso-ansi-font-size:10.0pt;
font-family:Wingdings;}
ol
{margin-bottom:0in;}
ul
{margin-bottom:0in;}
--></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=WordSection1><p class=MsoNormal>Wrenches,<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I don’t believe this is a correct use. As was already pointed out, the correct size fuse for those two paralleled strings (assuming 60 cell, 230 or so watt module) would likely be 30 A:<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Isc = 8.2<o:p></o:p></p><p class=MsoNormal>82 A * 2 * 1.56 = 25.6 A = 30 A fuse<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>The max series fuse rating of the module is most likely 15 A. In the setup described below, the remaining four combined strings could certainly feed a fault at above the rating of the panel (15 A) but below the trip rating of the 30 A fuse.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>These Y type connectors are only good when there are 2 parallel strings TOTAL, or possibly three for certain SunPower or other modules as was pointed out.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Cheers,<o:p></o:p></p><p class=MsoNormal>-Nathan<o:p></o:p></p><p class=MsoNormal><b><o:p> </o:p></b></p><p class=MsoNormal>><b>penobscotsolar at midmaine.com</b> <a href="mailto:re-wrenches%40lists.re-wrenches.org?Subject=Re%3A%20%5BRE-wrenches%5D%20MC4%20Y%20Connectors&In-Reply-To=%3Ceddfba3bfc366ba4d3a5ca866c3b6da2.squirrel%40mail.myottmail.com%3E" title="[RE-wrenches] MC4 Y Connectors">penobscotsolar at midmaine.com </a><br><i>>Fri Mar 9 11:23:45 PST 2012</i> <o:p></o:p></p><p class=MsoNormal>><o:p> </o:p></p><pre>>My whole point is that this method is only good when you are paralleling<o:p></o:p></pre><pre>>two strings, per breaker/fuse, no more. The "Y's" only combine two<o:p></o:p></pre><pre>>strings. That allows an installer to cut in half the amount of<o:p></o:p></pre><pre>>fusible/breakered strings in an installation. If you have 10 strings of<o:p></o:p></pre><pre>>three panels you can parallel two sets of three panel strings five times.<o:p></o:p></pre><pre>>This is an efficient design approach saving both installer time and the<o:p></o:p></pre><pre>>customer money while fully protecting the system. It also makes wire<o:p></o:p></pre><pre>>management much more aesthetically pleasing.<o:p></o:p></pre><pre>><o:p> </o:p></pre><pre>>Daryl<o:p></o:p></pre><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>--<o:p></o:p></p><p class=MsoNormal>Nathan J. Stumpff - Actic Sun, LLC<o:p></o:p></p><p class=MsoNormal><a href="mailto:nathan@arcticsun-llc.com">nathan@arcticsun-llc.com</a><o:p></o:p></p><p class=MsoNormal>Office: 907/457-1297<o:p></o:p></p><p class=MsoNormal>Cell: 917/992-7577<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p></div></body></html>