Separation is an issue the NEC does not address clearly .However, please make
sure you allow adequate room to repair the conduit if damaged, and 12' seems to be the magic number. I lso had no luck looking in 490.<br><br>NEC 300.4(C)(2)(e) also seems a bit relevant where it allows for
conductors of different voltage ratings in manholes "if the conductors
of each system are permanently and effectively separated from the
conductors of the other systems...", but again this may be referring to separate trenches with different system voltage ratings entering the
same manhole for tapping, allowing access for maintenance or other uses.
<br><br><br><br><div class="gmail_quote">On Thu, Nov 3, 2011 at 5:42 PM, Jerry Caldwell <span dir="ltr"><<a href="mailto:solarcowboy@yahoo.com">solarcowboy@yahoo.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
<div><div style="color:#000;background-color:#fff;font-family:times new roman, new york, times, serif;font-size:12pt"><div><span>Can anyone direct me to the NEC article that stipulates how many inches of separation must be between cables operating at different voltages?</span></div>
<div><span><br></span></div><div><span>I have a project with PV combiner box home runs at 1,000 volts DC in the same trench with 12.47 kV cables. Table 300.5 shows minimum cover requirements for direct burial cables, but this is the distance beneath grade the cables must be. Is there anywhere in the code that calls for a minimum separation distance between cables at different voltages?</span></div>
<div><span><br></span></div><div>Thanks,</div><div>Jerry Caldwell</div><div><br></div><div><br></div><div><br></div><div style="font-size:12pt;font-family:'times new roman', 'new york', times, serif"><div style="font-size:12pt;font-family:'times new roman', 'new york', times, serif">
<font size="2" face="Arial"><hr size="1"><b><span style="font-weight:bold">From:</span></b> Marco Mangelsdorf <<a href="mailto:marco@pvthawaii.com" target="_blank">marco@pvthawaii.com</a>><br><b><span style="font-weight:bold">To:</span></b> 'RE-wrenches' <<a href="mailto:re-wrenches@lists.re-wrenches.org" target="_blank">re-wrenches@lists.re-wrenches.org</a>><br>
<b><span style="font-weight:bold">Sent:</span></b> Thursday, November 3, 2011 2:27 PM<br><b><span style="font-weight:bold">Subject:</span></b> [RE-wrenches] under performing Enphase inverters<br></font><br>
<div>
<div>
<div>
<div>For the first time, several weeks ago, after 40-50 Enphase
installs, we’ve come across at least two M210s that we putting out
consistently lower outputs than their immediate neighbors.</div>
<div> </div>
<div>We replaced the two mods first, which made no
difference. Then, in consultation with Enphase, replaced the M210s.
After replacing them, the power output was as it should be.</div>
<div> </div>
<div>Now I’ve got another suspect system with several
underperforming mods out of (36).</div>
<div> </div>
<div>Has anyone else had this experience?</div>
<div> </div>
<div>Thanks,</div>
<div>marco</div>
<div> </div>
</div>
</div>
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<br></blockquote></div><br><br clear="all"><br>-- <br><b>James B Rudolph<br>NABCEP Certified PV Installer<br><br></b><br>