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Drake;<br>
<br>
I had trouble finding that reference, then I found it in the back in
Annex B. I think that would apply to the ampacity of the DC line,
but then for the 12.47 Kv line, I believe you would need Figure
310.60 which then references Tables 310.60 C (77) thru Table 310.60
c (86)<br>
Without knowing more details, it looks like Jerry would need 24"
spacing (see details 6,8, or 10).<br>
This seems like an issue that you'd want a PE to double check and
sign off on, as that is a fairly high AC voltage, and there could
possibly be a significant induced AC voltage on the DC line
(especially if its a long shared ditch). <br>
<br>
Ray Walters<br>
<br>
On 11/6/2011 8:36 AM, Drake wrote:
<blockquote
cite="mid:20111106153640.D88E83A4061@homiemail-a54.g.dreamhost.com"
type="cite">
Check out Figure Figure B.310.15(B)(2)(1) <br>
<br>
<br>
<br>
At 07:43 AM 11/4/2011, you wrote:<br>
<blockquote type="cite" class="cite" cite="">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>
On Thu, Nov 3, 2011 at 5:42 PM, Jerry Caldwell
<<a moz-do-not-send="true"
href="mailto:solarcowboy@yahoo.com">solarcowboy@yahoo.com</a>>
wrote:<br>
<dl>
<dd>Can anyone direct me to the NEC article that stipulates
how many
inches of separation must be between cables operating at
different
voltages?<br>
<br>
</dd>
<dd>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?<br>
<br>
</dd>
<dd>Thanks,<br>
</dd>
<dd>Jerry Caldwell<br>
<br>
<br>
<br>
<br>
</dd>
<dd><font size="2">From: Marco Mangelsdorf
<<a moz-do-not-send="true"
href="mailto:marco@pvthawaii.com">marco@pvthawaii.com</a>><br>
</font></dd>
<dd><font size="2">To: 'RE-wrenches'
<<a moz-do-not-send="true"
href="mailto:re-wrenches@lists.re-wrenches.org">
re-wrenches@lists.re-wrenches.org</a>><br>
</font></dd>
<dd><font size="2">Sent: Thursday, November 3, 2011 2:27 PM<br>
</font></dd>
<dd><font size="2">Subject: [RE-wrenches] under performing
Enphase inverters<br>
</font><br>
</dd>
<dd>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.<br>
</dd>
<dd> <br>
</dd>
<dd>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.<br>
</dd>
<dd> <br>
</dd>
<dd>Now I’ve got another suspect system with several
underperforming mods
out of (36).<br>
</dd>
<dd> <br>
</dd>
<dd>Has anyone else had this experience?<br>
</dd>
<dd> <br>
</dd>
<dd>Thanks,<br>
</dd>
<dd>marco<br>
</dd>
<dd> <br>
<br>
</dd>
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<br>
-- <br>
James B Rudolph<br>
NABCEP Certified PV Installer<br>
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<x-sigsep>
<p>
<font size="2">Drake
Chamberlin<x-tab> </x-tab>
<br>
ATHENS ELECTRIC LLC<br>
OH License
44810<x-tab> </x-tab><br>
CO license 3773<br>
NABCEP Certified PV<br>
</font>
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