<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto"><div>I wonder if the afci disturbances are caused (in part) at all from the wire size used on the AC side in the inverter?</div><div>I just noticed the Sunny Tripower, which has a max AC output current of 14.5A, states in the manual that it <u>requires</u> #8 or #6. ? </div><div>That is pretty big wire for 14A, don't ya think? What is the reasoning behind requiring such a large wire size?</div><div>With our 4 inverters being within 15' of the AC panelboard, voltage drop is not an issue and first thought is to go with #12. </div><div>I suspect it has to do with the terminal block in the inverter. I checked and the #12 holds pretty tight, but that doesn't mean it was approved for #12. <br> </div><div><div><span class="Apple-style-span" style="-webkit-tap-highlight-color: rgba(26, 26, 26, 0.296875); -webkit-composition-fill-color: rgba(175, 192, 227, 0.230469); -webkit-composition-frame-color: rgba(77, 128, 180, 0.230469); ">benn</span></div></div><div><br>On Jun 25, 2014, at 10:46 AM, Steve Jefferson <<a href="mailto:Steve.Jefferson@sma-america.com">Steve.Jefferson@sma-america.com</a>> wrote:<br><br></div><blockquote type="cite"><div>
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<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>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">For the 6 years I have been with SMA, I (and Service as a whole) will always advise against using wire nuts.<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">For the 13 years I have been in the solar industry, there are only a handful of systems that I have installed that I used wire nuts.<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">There is no cover up. This has been in our manuals since the beginning of SMA.<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 AFCI circuit is really sensitive to noise, therefore eliminating most possibilities of issues that installers may come across is our goal.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Wire nuts is a simple thing to not use, and there are many alternatives.<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:10.0pt;font-family:"Arial","sans-serif";color:#1F497D">SMA America, LLC<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D">Steve Jefferson<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D">Service Line Supervisor<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D">3925 Atherton Ave<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D">Rocklin, CA 95765 - 3714<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D">Tel: +1 916 625 3185 (direct)<o:p></o:p></span></p>
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</span><u><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:blue"><a href="mailto:Steve.jefferson@SMA-America.com">Steve.jefferson@SMA-America.com</a></span></u><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D"><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","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 [<a href="mailto:re-wrenches-bounces@lists.re-wrenches.org">mailto:re-wrenches-bounces@lists.re-wrenches.org</a>]
<b>On Behalf Of </b>Bill Hoffer<br>
<b>Sent:</b> Wednesday, June 25, 2014 9:13 AM<br>
<b>To:</b> RE-wrenches<br>
<b>Subject:</b> Re: [RE-wrenches] AFCI disturbances.<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
<div>
<p class="MsoNormal">William<o:p></o:p></p>
<div>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
<div>
<p class="MsoNormal">I agree with Bob-O, wire nuts are not the best choice for DC connections, for all the reasons he mentioned, but SMA claiming that wire nuts are causing arc faults seems like a long shot at covering up an arc fault detection nuisance tripping
problem. IMHO AFCI protection circuits are far from perfected at this time and Inverters and optimizers have enough inherent switching noise to cause nuisance tripping ( and there is ample evidence supporting numerous inverter manufacturers having issues).
I believe we are going to have similar growing pains as we did in the beginning of requiring ARC Fault panel mounted breakers for bedrooms. I have since replaced all my Square D Arc Fault breakers due to failure, ie nuisance tripping. I understand the intent
of adding arc fault to the 2014 code, but I am concerned that as installers we will again become the guinea pigs in this crazy experiment! Don't gt me started on the fact that they are required to only detect series faults and that opening the circuit on
a parallel fault will likely make the arc increase rather than extinguish! <o:p></o:p></p>
</div>
<div>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
<div>
<p class="MsoNormal">Bill<o:p></o:p></p>
</div>
</div>
<div>
<p class="MsoNormal" style="margin-bottom:12.0pt"><o:p> </o:p></p>
<div>
<p class="MsoNormal">On Wed, Jun 25, 2014 at 8:40 AM, William Miller <<a href="mailto:william@millersolar.com" target="_blank">william@millersolar.com</a>> wrote:<o:p></o:p></p>
<p class="MsoNormal">Richard:<br>
<br>
Possibly. I think I prefer din mount connector blocks. However, if a wire nut can arc internally a connector block might also. I am still wondering about this concept.<br>
<br>
William<br>
<br>
Miller Solar<br>
<br>
> On Jun 25, 2014, at 6:09 AM, <a href="mailto:Richard.L.Ratico@valley.net">Richard.L.Ratico@valley.net</a> (Richard L Ratico) wrote:<br>
><br>
> William,<br>
> Would UL listed crimp sleeves be an acceptable substitute where you would<br>
> otherwise use wirenuts?<br>
><br>
> Dick Ratico<br>
> Solarwind Electric<o:p></o:p></p>
<div>
<div>
<p class="MsoNormal">><br>
><br>
> --- You wrote:<br>
> Bob-O:<br>
><br>
><br>
><br>
> When you say verboten, what does that mean? Not kosher? Frowned upon?<br>
> Disallowed by law???<br>
><br>
><br>
><br>
> I am quite curious about this subject. Here is what I have learned so far:<br>
><br>
><br>
><br>
> This is a unique case where we are replacing 3 dead SMA U series inverters<br>
> with 2 US series inverters. The U series seem to all be dying at about 12<br>
> to 14 years of age. We have about a dozen of these to swap on our calendar<br>
> and expect more. It may be that to do this right requires that we pull new<br>
> wire from the arrays. This makes the job a lot more expensive.<br>
><br>
><br>
><br>
> We have never used a wire nut on a PV lead until this project. It's not<br>
> that we disapprove of wire nuts in general, it is because we know that if we<br>
> were to use them regularly we would eventually have failures and call backs.<br>
> We allow only one splice in a PV lead: between the cable provided by the<br>
> manufacturer of the module and a bulkhead mounted MC4 connector direct to<br>
> THWN in conduit<br>
> (<a href="http://millersolar.com/MillerSolar/practices/PV_wiring/PV_Cable_wiring/_PV_" target="_blank">http://millersolar.com/MillerSolar/practices/PV_wiring/PV_Cable_wiring/_PV_</a><br>
> Cable_Wiring.html).<br>
><br>
><br>
><br>
> We checked the manufacturer's listing and the wire nuts are rated for 600<br>
> volts. We do use wire nuts on AC circuits, such as switch and receptacle<br>
> circuits in a power room.<br>
><br>
><br>
><br>
> A tech at SMA told me that wire nuts "arc internally to the spring" causing<br>
> the AFCI faults. I am not aware of any process of "internal arcing." To<br>
> me, arcing means, as per the dictionary definition: "a luminous bridge<br>
> formed in a gap between two electrodes." The same tech told me to solder<br>
> the leads and apply shrink tubing. I don't believe this is an approved<br>
> method. By the way, we have spliced leads on both US series inverters and<br>
> only one is exhibiting AFCI disturbances.<br>
><br>
><br>
><br>
> I do favor mounted terminal blocks, either screw or tubular type. I need to<br>
> check if the Amp model we stock are 600 volt rated.<br>
><br>
><br>
><br>
> I was told by another representative from SMA that on a ground-mount system<br>
> it is legal to disable the AFCI protection.<br>
><br>
><br>
><br>
> I will be troubleshooting this job tomorrow and I will let you all know what<br>
> I learn.<br>
><br>
><br>
><br>
> William Miller<o:p></o:p></p>
</div>
</div>
<p class="MsoNormal">> --- end of quote ---<o:p></o:p></p>
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<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">-- <o:p></o:p></p>
<div>
<div>
<p class="MsoNormal">William Hoffer <o:p></o:p></p>
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<p class="MsoNormal">161 SE Fourth Ave<o:p></o:p></p>
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<p class="MsoNormal" style="margin-bottom:12.0pt">P.O. Box 1823<br>
White Salmon, WA 98672-1823<br>
<a href="mailto:bhoffer@sunergyengineeringservices.com" target="_blank">sunengser@gmail.com</a><o:p></o:p></p>
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