The super flex of the SOWA cable would be the best option I believe. I
had heard that it is not approved for permanent installs, but 690.31(E)
appears to explicitly allow the use of this cable type for trackers, so
I think Dana's described method is the way to go, certainly better than
my old method.
R.Ray Walters
CTO, Solarray, Inc
Nabcep Certified PV Installer,
Licensed Master Electrician
Solar Design Engineer
303 505-8760
On 12/1/2015 10:25 AM, Dana wrote:
We install the array junction box (with breakers) on the upper portion
of the tracker & use SOWA cord for the drop with strain relief on both
ends. The lower box has the conduit back to the power center or
building breaker for Grid tie. Check with your AHJ but this cord is
sunlight-oil-gas rated, & comes in many gauges. Probably not the least
expensive option but never had one fail in 20+ years. Allow enough for
a full rotation but not so much it gets flailing about in the wind.
I build my own extension cords using the same and have cord that has
been on job sites for 20 years now. Again, not cheap but they last &
last.
I have replaced various flex non metallic seal tight conduit
installations by others when it has cracked. Also at cold temps the
nmst flex conduit does not bend very happily.
----------------------------------------------------------------------------
Dana Orzel
Great Solar Works, Inc - NABCEP # 051112-136
E - d...@solarwork.com - Web - solarwork.com
O - 970.626.5253 C - 208.721.7003
"Responsible Technologies for Responsible People since 1988"
*P*Please consider the environment before printing this email.
*From:*RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org]
*On Behalf Of *Ray Walters
*Sent:* Monday, November 30, 2015 8:35 PM
*To:* RE-wrenches
*Subject:* Re: [RE-wrenches] Wire management dual axis tracker
We used to just bundle the PV cables and secure them close to the
pivot point at both the rack and the pole with insulated wire loom
clamps. We always made a big enough loop to handle full articulation,
but not too long so they wouldn't catch on the Combiner box, etc. We
also started using braided ground strap, instead of stranded #6.
Braided is made for movement, stranded #6 would strain harden and
break off at the connector.
I'm not sure how flex conduit would do. It definitely could break out
of a plastic J box, I would think. The back and forth motion
eventually wears out things not really made to move. I had lots of
trouble with this issue.
Finally, don't be greedy on tracker settings, I'd keep the total range
of motion to less than a full 180 degrees Azimuth, and probably limit
the tilt some too.
R.Ray Walters
CTO, Solarray, Inc
Nabcep Certified PV Installer,
Licensed Master Electrician
Solar Design Engineer
303 505-8760
On 11/30/2015 8:21 PM, Mac Lewis wrote:
Hi Wrenches,
I'm looking for advice on the best way(s) to secure PV source
circuit wiring on a dual axis tracker. I've never wired one up
before and it seems tricky. This particular tracker is 12
modules, 3 strings. Is it best to run a flexible conduit up the
pole and leave plenty of excess conduit to create large loops that
fluctuate in size throughout the day? What are some other ideas?
How do you avoid abrasion over time?
Thanks in advance
--
Mac Lewis**
"Yo solo sé que no sé nada." *-Sócrates***
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