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<DIV dir=ltr align=left><FONT color=#0000ff size=2 face=Arial><SPAN
class=968545714-05032011>I guess the thinking is that DC side of
the Enphase is grounded and therefore a separately derived system requiring
it's own system grounding. This is achieved by connecting the GEC to the chassis
of the inverter. If the DC side of the inverter were ungrounded, then it would
not be a separately derived system and would not require it's own system ground.
At that point, would the AC side of the inverter still be considered a
separately derived system or would the need for system grounding go
away?</SPAN></FONT></DIV>
<DIV dir=ltr align=left><FONT color=#000000 size=2 face=Arial><SPAN
class=968545714-05032011></SPAN></FONT><SPAN lang=en-us><FONT size=2
face=Arial></FONT></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN lang=en-us><FONT size=2 face=Arial>Mark
Frye</FONT></SPAN> <BR><SPAN lang=en-us><FONT size=2 face=Arial>Berkeley Solar
Electric Systems</FONT></SPAN> <BR><SPAN lang=en-us><FONT size=2 face=Arial>303
Redbud Way</FONT></SPAN> <BR><SPAN lang=en-us><FONT size=2 face=Arial>Nevada
City, CA 95959</FONT></SPAN> <BR><SPAN lang=en-us><FONT size=2
face=Arial>(530) 401-8024</FONT></SPAN> <BR><SPAN lang=en-us></SPAN><A
href="http://www.berkeleysolar.com/"><SPAN lang=en-us><U><FONT color=#0000ff
size=2 face=Arial>www.berkeleysolar.com</FONT></U></SPAN></A><SPAN
lang=en-us><FONT size=2 face=Arial> </FONT></SPAN> </DIV>
<DIV> </DIV><BR>
<DIV dir=ltr lang=en-us class=OutlookMessageHeader align=left>
<HR tabIndex=-1>
<FONT size=2 face=Tahoma><B>From:</B> re-wrenches-bounces@lists.re-wrenches.org
[mailto:re-wrenches-bounces@lists.re-wrenches.org] <B>On Behalf Of </B>Bill
Brooks<BR><B>Sent:</B> Friday, March 04, 2011 5:51 PM<BR><B>To:</B>
'RE-wrenches'<BR><B>Subject:</B> Re: [RE-wrenches] grounding the Enphase
inverter<BR></FONT><BR></DIV>
<DIV></DIV>
<DIV class=WordSection1>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt">The
better question is why is there a solid ground in the inverter.
<o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt"><o:p> </o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt">As
I stated before—we are talking about system grounding—with 100+ years of
electrical history and precedent to back it up.<o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt"><o:p> </o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt">System
grounding rules are not open to a lot of discussion. That is why my
recommendation since before they released their first product was to go
ungrounded. Just because it is a pain, and we think there is no technical
reason, does not mean we can ignore the rules. As I said in my post, this is not
really a safety issue, but it is very much a compliance issue. System grounding
is so much a part of our electrical culture, that tiny electrical supplies like
PV microinverters were never really considered. <o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt"><o:p> </o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt">Any
installer can use the “don’t ask, don’t tell” method of installation, but once
we start down that path, the ability of the human mind to justify actions is
limitless. We have to go back to why we ground systems in the first place. It is
to prevent the voltage on the system conductors from wondering too far from
ground potential. There are other ways to prevent this, but in the U.S. we
mostly use conductors (not a variety of conductive materials without clear
ratings). The advent of the WEEB, with all its great benefits, does not
fundamentally change system grounding.<o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt"><o:p> </o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt">The
sooner we get PV systems ungrounded, or resistively grounded, the better the
whole U.S. PV industry will be. To that end, everyone should move to PV
Cable/Wire and modules with PV Cable/Wire so we are using better products than
USE-2 and we can easily transition to ungrounded inverters as they become more
available. We already have several so now is not a bad time to start thinking
about it.<o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt"><o:p> </o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt">Bill.</SPAN></P></DIV></BODY></HTML>