<table cellspacing="0" cellpadding="0" border="0" ><tr><td valign="top" style="font: inherit;"><DIV>Yes </DIV>
<DIV>"from all sources of supply", the transformerless inverter is a source of supply. BOTH legs of all strings should be fused. It has always been that strings shall be protected from all sources of supply, and only SMA had stated that it will not back feed, This nature of the transformerless inverter was commented on before on this list. <BR></DIV>
<DIV>I like the approach of breaking all leads so that I can Meger all leads. the PowerOne megers and displays the input lines on start up. I am an electrician, I want to keep getting older and working, I want to have an external to the inverter Disconnect, and fuse all strings. </DIV>
<DIV> </DIV>
<DIV>Thanks as always</DIV>
<DIV>DT<BR>--- On <B>Sat, 11/13/10, Eric Thomas <I><solarepiphany@gmail.com></I></B> wrote:<BR></DIV>
<BLOCKQUOTE style="BORDER-LEFT: rgb(16,16,255) 2px solid; PADDING-LEFT: 5px; MARGIN-LEFT: 5px"><BR>From: Eric Thomas <solarepiphany@gmail.com><BR>Subject: [RE-wrenches] Head Spinning..(Con) fused.<BR>To: RE-wrenches@lists.re-wrenches.org<BR>Date: Saturday, November 13, 2010, 10:40 PM<BR><BR>
<DIV id=yiv1658981875>Wrenches,<BR><BR>Can anyone shed guidance on the following for me? Should these strings be fused:<BR><BR>Total Modules: 44<BR>Total Strings: 4 strings of 11 <BR>Total Inverters: 2<BR><BR>Modules: Silicon Energy 195 Watt @ 8A<BR>Each string feeding an independent MPPT input on an Aurora PVI 4.2kW Inverter (there are 2 / Aurora)<BR>Inverter is transformerless (READ 690.35 (B))<BR><BR>Each strings passes through a shared SolaDeck jbox, no combining, and head directly to their own dedicated GE THN2261RDC DC Disconnect before entering a dedicated MPPT input on the inverter.<BR><BR>My big question is 690.9 (A) exception (b) which states I don't need ocpd as long as "The short circuit currents from all sources do not exceed the ampacity of the conductors."<BR><BR>Because all four strings pass through the same jboxs and conduit before reaching their disconnect and could potentially short together, should I fuse each string? <BR><BR>Or am I
just up too late reading code....?<BR><BR>Thanks for being a resource.<BR clear=all><BR>-- <BR>Eric Thomas<BR>Solar Epiphany LLC<BR>(206) 919-3014<BR><A href="http://www.solarepiphany.com/" rel=nofollow target=_blank>www.solarepiphany.com</A><BR><BR></DIV><BR>-----Inline Attachment Follows-----<BR><BR>
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