August,
I have made many a times a 1" or 3/4" steel threaded coupling welded to
a small pc of 3/16" X 1" X 3" long steel (coming off at a right angle). The
pc welded to the coupling has a 5/16" hole in it to be able to use the DPW
turn-bolt to secure it their rack just inboard of the edge of the array. In
one end of the coupling I install a strain relief, the other a carflex fitting
or EMT male adapter (TA)....I think you get the rest.
Its solid because the ends of the conduit are bolted to the rack and of
course you could secure midway if necessary, no roof penetrations, usually. Of
course this only works for ~4, 10 Ga. 'PV wire' size wires, but its one option.
Could include a pic but currently on vacation.
Bill
Feather River Solar Electric
----- Original Message -----
From: August Goers
To: RE-wrenches
Sent: Tuesday, August 11, 2015 3:19 PM
Subject: [RE-wrenches] wiring methods between arrays
Hi Wrenches,
I have another best practices questions: what are you doing to run your PV
wire between arrays on a rooftops? This question has come up on this list in
the past but I’m still on the hunt for a robust and faster lower cost method.
We mostly install outdoor boxes on each sub array and then run EMT between
these boxes. We use strain reliefs to enter the boxes and then either keep PV
wire or transition to THWN-2 in the EMT depending on the layout. This method
takes time and the outdoor boxes aren’t cheap. Alternatively, we can run
open-ended EMT with ground bushings on the ends to bond the conduit. Since
ground bushings are designed to be used in boxes we switch out the aluminum lug
with a tin-coated outdoor rated lug and stainless hardware. This technically
violates the listing but at least the materials hold up. The EMT needs to be
carefully bent down at the ends so rain doesn’t enter. Lastly, we sometimes run
our PV wires along strut or angle aluminum (this is the fastest method) which
also needs to be bonded with a lay-in lug.
Does anyone have other methods?
Best,
August
Luminalt
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