Conrad Geyser wrote:
We always fill any conduit at the point of building penetrations for
air sealing. Otherwise in winter, not only will the conduit get house
moisture condensing inside of it, but it will act a a nice thermo
siphon for pulling warm air out of the house…..
Just a note here...
All six of the MidNite PV combiner boxes are rain "proof", but allow moisture
to escape.
boB
------------------------------------------------------------------------
*From:* re-wrenches-boun...@lists.re-wrenches.org
[mailto:re-wrenches-boun...@lists.re-wrenches.org] *On Behalf Of
*Wind-sun.com
*Sent:* Tuesday, August 25, 2009 11:49 AM
*To:* jry...@netscape.com; RE-wrenches
*Subject:* Re: [RE-wrenches] raintite box mounting angle
It is almost impossible in a normal installation to get a totally
waterproof enclosure.
What you describe with the flooded box is more common than people
might think.
What causes most of that is condensation. Humid air gets sucked into
the enclosure at night or whenever else it cools off. The water then
condenses inside. Next day, the box heats up again and the air expands
a bit again, but the water has already condensed and cannot get out.
That is why the weep hole as you noted is mandatory, especially in
areas with high humidity. But we have seen this even in the desert
regions of Arizona and CA, so it can happen anyplace over long periods
of time.
..................................................................................................
Northern Arizona Wind & Sun - Electricity >From The Sun Since 1979
Solar Discussion Forum: http://www.wind-sun.com/ForumVB/
..................................................................................................
----- Original Message -----
*From:* Jeff Yago <mailto:jry...@netscape.com>
*To:* k...@vtsolar.com <mailto:k...@vtsolar.com> ; RE-wrenches
<mailto:re-wrenches@lists.re-wrenches.org>
*Sent:* Tuesday, August 25, 2009 8:40 AM
*Subject:* Re: [RE-wrenches] raintite box mounting angle
I am getting more convinced that there is no such thing as a
water-tight electrical enclosure, regardless of gasket covers and
sealed openings. We always drill a very small "weep-hole" in the
bottom of an enclosure. We have found this is too small to allow
insects to enter, but will drain any leaks or moisture that gets
condensed into a liquid. I was recently called by the owner of a
large pole mounted array (that was installed by another firm )
when the system stopped working and the originally installer was
long gone. I absolutely swear to you that when I pulled the covers
off several electrical junctions boxes, water POURED out of the
enclosures! I am not talking about wet, I am saying about a quart
of water was being held inside each enclosure by their water-proof
gasketed covers. Needless to say, all of the electrical terminals
and wire connectors inside these junction boxes were badly corroded.
I know they make totally water-proof electrical equipment for
under-water applications, but have found most outdoor rated
electical enclosures will get some water inside and that includes
under-ground conduit. Take some advice and regardless of mounting
orientation, drill a small weep-hole in the bottom if there is not
one provided by the manufacturer.
Jeff Yago
DTI Solar
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