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    <p><font face="Verdana">I think something on the order <font
          face="Verdana">of 90+% lig<font face="Verdana">htnin<font
              face="Verdana">g strikes come from the utili<font
                face="Verdana">ty feed, not the dc side. That has to be
                ignored if in a high str<font face="Verdana">ike area or<font
                    face="Verdana"> grid is<font face="Verdana">olated.
                    </font></font></font></font></font></font></font></font><br>
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    <br>
    <div class="moz-cite-prefix">On 10/8/2018 10:37 PM, Ray wrote:<br>
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      cite="mid:50c7a8a6-0a86-90cf-0075-c5d755da1069@solarray.com">
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      <p>I believe you can use the SPD 300 AC on 2 strings, if PV neg is
        grounded.  You would connect the green to ground (or PV neg) and
        then connect the red to one string pos, and connect the black to
        the other string pos.  This would be limited to 300 v also.  I
        haven't tried that exact configuration, but I have used the 300
        AC to protect both the AC in and AC out on 120 vac inverters.  I
        also believe you can use a 600 DC version, and wire as I
        mentioned, but the LEDs won't light. If you are using ungrounded
        inverters, then I think you would need an SPD for each string in
        order to protect both the pos and neg of each string, like
        you've been doing.</p>
      <p>Maybe someone from Midnite can clarify this.</p>
      <p>As far as it being worth it, I haven't had lightning related
        damage since I started using the Midnite SPDs, and I used to
        have system damage every year.  If you are not in lightning
        country, or the install is in a low spot with less likelihood of
        taking a hit, you might be able to skimp.  But for some of these
        off grid ridge top installs, I consider it a must. Some times I
        don't install one on the gen circuit, if its really close.<br>
      </p>
      <p>  <br>
      </p>
      <pre class="moz-signature" cols="72">Ray Walters
Remote Solar
303 505-8760</pre>
      <div class="moz-cite-prefix">On 10/8/18 4:03 PM, Drake wrote:<br>
      </div>
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        cite="mid:20181008220322.B75F41071B1@pdx1-mailman03.dreamhost.com">
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        Hello Wrenches,<br>
        <br>
        Do you use surge arrestors with multi MPPT input string
        inverters? Do you put a separate arrestor on each MPPT input? I
        find it sort of pricey using a Midnite Solar arrestor on each
        string, but have been doing that. Is there a less expensive
        approach that is effective? <br>
        <br>
        I believe the Midnite units are the best. Are they worth the
        expense?<br>
        <br>
        Thank you,<br>
        <br>
        Drake<br>
         <br>
         <br>
        <a name="_MailAutoSig" moz-do-not-send="true"></a>Drake
        Chamberlin<br>
        <i>Athens Electric LLC<br>
          OH License 44810<br>
          CO License 3773<br>
          NABCEP Certified Solar PV <br>
          740-448-7328<br>
        </i><a href="http://athens-electric.com/" moz-do-not-send="true">http://athens-electric.com/</a>
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