[RE-wrenches] Helical Anchors for Ground-Mount

[William Miller]

Eric:



Have you considered driven-pipe?  Hereabouts there are several contractors
set up with Bob-cat mounted drivers for corral fencing. They are also
equipped to weld.



We have been using driven pipe for DPW LGM arrays.  Recently we came upon a
steep E-W slope that needed a low profile PV. Every off-the-shelf solution
requires a 90 degree angle between the verticals and the horizontals.  This
would make an array very tall down-slope.  The contractor was able to drive
verticals and then custom fit “horizontals” parallel with the slope.  See
image below.  We used only the top brackets and rails from the LGM package
and it worked out quite well.  We moved the verticals out-board 8” front
and back and wrapped the entire assembly in 1”X2” stock fencing to prevent
access to wiring.



One local jurisdiction requires no engineering for structures less than 6’
in height.  Others require engineering on all ground mounts, so you see the
response can be varied.  We have found a couple structural engineers that
are quite reasonable in cost, typically $300-400.



Driven pipe passed structural analysis for us only for low tilt arrays.
High-tilt arrays became impractical due to requirements to drive pipe
excessively deep.  Engineering did allow us to reduce the amount of
concrete on the packaged designs provided by DPW.



Good luck,



William





[image: Gradient Cap_mini]
Lic 773985
millersolar.com <http://www.millersolar.com/>
805-438-5600



*From:* RE-wrenches [mailto:re-wrenches-bounces at lists.re-wrenches.org] *On
Behalf Of *eric at harvesthesun.com
*Sent:* Thursday, March 31, 2016 10:19 AM
*To:* RE-wrenches
*Cc:* Ian.isbell at thatsbyers.com
*Subject:* [RE-wrenches] Helical Anchors for Ground-Mount



We're considering moving away from concrete footings where appropriate on
GM projects. I am have not used any helical anchor systems and am curious
about the efficiency of the helical anchor system in resi applications.
Specifically, am I going to need soil compaction tests and/or geo survey
with a P.G. stamp? What is the AHJ going to be looking for? As always, I
appreciate any input!



Eric Stikes

Founding Director & CEO

Good Sun Solar, A CA non-profit corp.

www.goodsun.life

(530)798-3738
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