I just ran into this on a new Dasol 12 v module. I ended up wiring with
USE but couldn't do the series connections. I had to bring each module
wire into a J Box. I'm now using Kyocera, as that was a PITA. Since
your project is low amperage, have you considered smaller USE like 12 or
14 GA? I actually even keep 16 and 18 AWG TC around for little
modules. The volt drop isn't as bad as you might imagine, and 18 awg
actually has a free air rating of 18 amps (crazy huh? though 240.4(D)1
limits it to 5.6 amps continuous.)
R.Ray Walters
CTO, Solarray, Inc
Nabcep Certified PV Installer,
Licensed Master Electrician
Solar Design Engineer
303 505-8760
On 10/9/2013 11:48 PM, Allan Sindelar wrote:
Wrenches,
I do a fair amount of work on ancient systems, just because there's
been off grid here for decades. I'm rewiring several old arrays for my
next door (meaning < 1/4 mile away) neighbor. The particular array has
six 53W Solec modules wired as three two-module 24V pairs, on a
Zomeworks tracker so old that it has aluminum rails and attached freon
canisters instead of the integral square tubes. Both modules and
tracker continue to work well, but the wiring is so degraded from sun
exposure that's it's bare in spots, and this is what I want to fix.
Each module has a tiny j-box - 3" x 3" x 7/8" deep. Each j-box has a
single 3/8" cord grip bushing (CGB). Each bushing has two #10
conductors coming out of the single hole in the CGB. The O.D. of each
wire is about the same as that of THWN. The problem is that the single
hole in the CGB is only large enough to fit this diameter. USE-2 is
too large, and modern PV wire is way too large.
I bought a dozen replacement 3/8" CGBs from Del City, but the matching
lock rings are too large to fit inside the j-boxes. I'd be cautious
about using a narrow Unibit to drill an additional hole in each j-box
anyway, given that the holes would be so close to the backsheet.
The easiest solution would be to find some sunlight-resistant,
wet-rated single-conductor wire in #10 or #12 that has an insulation
O.D. about the same as THHN/THWN. Any ideas, please? Code is not an
issue in this instance - I just want a solution that works.
I thought about using float switch cable, which is UV-resistant,
wet-rated, direct-burial-rated type TC. We keep plenty in stock for
signal circuits, and it fits and is strong. The problem is that I need
single conductors, because each module will have one series conductor
and one output conductor, and they run to different locations.
Are there any better ideas out there?
Thanks, Allan
--
*Allan Sindelar*
[email protected]_ <mailto:[email protected]>
NABCEP Certified PV Installation Professional
NABCEP Certified Technical Sales Professional
New Mexico EE98J Journeyman Electrician
Founder, *Positive Energy, Inc.*
A Certified B Corporation^TM
3209 Richards Lane
Santa Fe, New Mexico 87507
*505 424-1112 office 780-2738 cell*
_www.positiveenergysolar.com_ <http://www.positiveenergysolar.com/>
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