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<font size=3>Jay:<br><br>
I use a spreadsheet I created for voltage drop calculations. I have
upgraded it periodically and recently added columns to indicate de-rated
ampacities due to temperature and conduit fill. This spreadsheet is
available at:
<a href="http://mpandc.com/resources/resources.html" eudora="autourl">http://mpandc.com/resources/resources.html</a><br><br>
As a caveat, I don't use Excel as my native spreadsheet language, but I
port tools I want to make available to the public to Excel as it is a
more commonly used application. No guarantee is implied on the use
of this tool and I do appreciate any feedback.<br><br>
William Miller<br><br>
<br><br>
At 10:37 PM 1/13/2009, you wrote:<br><br>
<br>
<blockquote type=cite class=cite cite><blockquote type=cite class=cite cite>Hi
Bill,<br><br>
Who puts this into a spread sheet or computer program?<br><br>
thanks,<br><br>
jay<br><br>
peltz power<br>
On Jan 8, 2009, at 11:56 AM, Bill Brooks wrote:<br><br>
<blockquote type=cite class=cite cite>Peter,<br><br>
We cannot use load diversity to increase the number of conductors
in <br>
a PV<br>
conduit since there generally is little diversity among the <br>
conductors,<br>
particularly on large arrays.<br><br>
The more traditional conduit adjustment table to use is Table<br>
310.15(B)(2)(a). The value from this table is multiplied by the
<br>
temperature<br>
adjustment factor in Table 310.16. The key is what to use as the
<br>
ambient<br>
temperature in Table 310.16. We also have the third adjustment of
<br>
Table<br>
310.15(B)(2)(c) in the 2008 NEC for conduit close to rooftops. Even
<br>
if you<br>
are excused from using the 2008 NEC by a jurisdiction, the 2005 NEC
<br>
has<br>
310.10 FPN2 that generally recommends a 17C adder on ambient <br>
temperature.<br>
engineers doing HVAC wiring are just now learning this stuff.<br><br>
Most inspectors will quickly cite the fact that the ampacity cannot
be<br>
greater than the 75C column, so we check to make sure (nearly
always <br>
is just<br>
fine).</font></blockquote></blockquote></blockquote></body>
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