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<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Ray,<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'>The reason I mentioned resistively grounded systems is that
anything requires a ground, like SunPower, could use a resistive ground instead
of being ungrounded. This solves SunPower polarization issue and is the way
many of their systems are installed in Europe.<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'>Bill.<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>
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<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>R Ray
Walters<br>
<b>Sent:</b> Tuesday, October 19, 2010 10:50 AM<br>
<b>To:</b> RE-wrenches<br>
<b>Subject:</b> Re: [RE-wrenches] BAKERSFIELD FIRE former "Target
fire"<o:p></o:p></span></p>
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<p class=MsoNormal><span style='font-size:7.0pt;font-family:"Helvetica","sans-serif";
color:black'>R. Walters<o:p></o:p></span></p>
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<p class=MsoNormal><span style='font-size:7.0pt;font-family:"Helvetica","sans-serif";
color:black'><a href="mailto:ray@solarray.com">ray@solarray.com</a><o:p></o:p></span></p>
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<p class=MsoNormal><span style='font-size:7.0pt;font-family:"Helvetica","sans-serif";
color:black'>Solar Engineer<o:p></o:p></span></p>
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<p class=MsoNormal>HI Bill;<o:p></o:p></p>
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<p class=MsoNormal><o:p> </o:p></p>
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<p class=MsoNormal>Where do we sign your petition?<o:p></o:p></p>
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<p class=MsoNormal>I've advocated for ungrounded systems for over a decade.
Besides Europe, electric vehicles and mobile systems are long standing examples
that this is safe. It also solves IMHO some lightning issues, and is easier to
work on (less accidental short circuits to frames and boxes)<o:p></o:p></p>
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<p class=MsoNormal>I've done numerous ungrounded systems, and never had any
problems. (We still of course bonded all exposed metal to ground, with EGCs run
with the conductors)<o:p></o:p></p>
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<p class=MsoNormal>My question is how do Sunpower modules behave ungrounded? I
was under the impression that they had to have positive bonded to ground to
function properly. Your proposed "Temporary Ground Lift" circuit
would probably be the best way for Sunpower modules?<o:p></o:p></p>
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<p class=MsoNormal><o:p> </o:p></p>
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<p class=MsoNormal>Thanks for your always thorough education of us numb nuts in
the field,<o:p></o:p></p>
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<p class=MsoNormal><o:p> </o:p></p>
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<p class=MsoNormal>Ray Walters<o:p></o:p></p>
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<p class=MsoNormal><br>
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<o:p></o:p></p>
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<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Moving to ungrounded or resistively grounded arrays is
relatively easy and the NEC covers the requirements in 690.35. We already have
several transformerless designs from Power-One and SMA (new TL line in the
U.S.), but there is nothing holding back larger inverters using transformers
with ungrounded arrays. Existing arrays could be made much safer if they were
to be retrofitted with a circuit at the inverter that would lift the grounded
conductor each morning and test for ground faults on the grounded conductor
prior to starting the inverter. While not quite as safe as
“European-style” systems, it is a large improvement over where we
are today. Don’t be surprised if things change about how we do GFPs soon.
If I have anything to do with it, it is going to happen. The current hazardous
situation, and bad information about the Bakersfield fire, cannot continue.</span><o:p></o:p></p>
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<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'> </span><o:p></o:p></p>
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<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Bill.</span><o:p></o:p></p>
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color:#1F497D'> </span><o:p></o:p></p>
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<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Bill Brooks, PE</span><o:p></o:p></p>
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<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Principal</span><o:p></o:p></p>
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<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Brooks Engineering</span><o:p></o:p></p>
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<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>873 Kells Circle</span><o:p></o:p></p>
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<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Vacaville, CA 95688</span><o:p></o:p></p>
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<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>707-332-0761 (office and mobile)</span><o:p></o:p></p>
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<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>707-451-7739 (fax)</span><o:p></o:p></p>
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<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><a href="mailto:bill@brooksolar.com">bill@brooksolar.com</a><span
class=apple-converted-space> </span>(email)</span><o:p></o:p></p>
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<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><a href="http://www.brooksolar.com/">www.brooksolar.com</a><span
class=apple-converted-space> </span>(web)</span><o:p></o:p></p>
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