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William,<br>
<br>
Metal is only required from the point that the PV circuit enters the
building to the first accessible disconnect, outside the building
plastic is okay. For underground plastic is definitely best. Here the
inspectors have been happy with plastic being used inside the building
for 3 or 4 feet from the floor up to the disconnect. The rational is
that a fire fighter us not likely to cut through it.<br>
<br>
Yes, 100 volts isn't as much of a hazard as 400 to 600 volts. But it
is still a hazardous voltage and it makes nice arcs too.<br>
<br>
I believe most combiner boxes don't qualify as a disconnect device
because it takes a screw driver to open them before you can turn
anything off. <br>
<br>
Kent Osterberg<br>
Blue Mountain Solar<br>
<br>
<br>
William Miller wrote:
<blockquote cite="mid:6.0.1.1.2.20090607173711.03af6ec0@millersolar.com"
type="cite"><font size="3">Kent:<br>
<br>
Interesting... <br>
<br>
What if the array is ground mount? I prefer not to have metallic
conduit underground. Fortunately, for off-grid we often have a
combiner on the rack that qualifies for a disconnecting means.<br>
<br>
Also, off-grid Voc is on the order of 100 volts, as opposed to 400 to
600.<br>
<br>
William<br>
<br>
<br>
<br>
At 04:01 PM 6/7/2009, you wrote:<br>
</font>
<blockquote type="cite" class="cite" cite=""><font size="3">William,<br>
<br>
It is interesting that the 2008 code also has the
"utility-interactive" typo. None the less, it is
appropriate to put photovoltaic circuits in metal conduit for off grid
systems. The risk to fire fighters is nearly the same in both
cases.<br>
<br>
Kent Osterberg<br>
Blue Mountain Solar<br>
</font></blockquote>
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