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<font size=3>August:<br><br>
As discussed, PVC is sometimes the best solution in a corrosive
environment. I would never recommend supporting PVC as depicted in
the photos. Shooting a screw through comp roofing is questionable
at best. Better methods of installing PVC are available, including
better straps and painting for UV protection.<br><br>
I might add that although I would not tolerate brown PVC, UV browning
does not render the conduit unusable. The browning is only a few
microns thick. This is why the conduit says "UV
resistant".<br><br>
For hangers, I suggest a better anchoring system. We use aluminum
strut with stainless fasteners and hangers. From our previous life
as a tower rigging firm we have brought over stainless telecommunications
hardware:
<a href="http://awapps.commscope.com/catalog/andrew/product_details.aspx?id=13158" eudora="autourl">http://awapps.commscope.com/catalog/andrew/product_details.aspx?id=13158</a>
This is available in various sizes<br><br>
William Miller<br><br>
<br><br>
At 11:26 AM 10/9/2009, you wrote:<br>
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All –<br>
<br>
PVC doesn’t hold up well in the Bay Area – Here’s a photo of some
~4 year old PVC browned PVC from Marin County:<br>
<br>
<img src="cid:6.0.1.1.2.20091009132801.039cfec0@millersolar.com.1" width=341 height=150 alt="83877e5.jpg"><br>
<br>
You can see that the straps melted resulting in the conduit sliding down.
Thank goodness we didn’t install this. PCV seems like a good option for
shaded areas. <br>
<br>
As Bill pointed out, if we use EMT we need to bond both ends of the
conduit to comply with NEC 250.97. My issue is that it is hard to find
outdoor rated bonding bushings – that’s why we’ve just been installing
cast metal boxes with threaded connections (complies with NEC
250.92(B)(2)).<br>
<br>
As William point out, EMT is robust and reliable. I still think that
there must be more efficient way to go between arrays. Maybe that’s why
commercial low profile racking systems are often fully integrated systems
with built in wire raceways.<br>
<br>
-August<br>
<br>
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