7kW ground mount system - AHJ signed off

[PocoEV]

Started researching a PV system back in June and appreciated the expertise here. Purchased panels in September and AHJ signed off in October. Here is a quick overview of the system with some pictures. Hope this might help someone else....

24 SolarWorld SW290 panels. (Voc = 475VDC and Vmpp = 383VDC Impp = 9.2amps) located 300 feet away from a SunnyBoy 7.0-US.
Two DC disconnects (SquareD HU361RB) one for each string of 12 panels.
8 foot 5/8" grounding rod for PV array and DC disconnects.
300 feet of 10AWG THWN copper to Inverter (4 wires buried 24" deep in 3/4" PVC conduit)
SunnyBoy 7.0-US mounted on exterior basement wall. Built in DC disconnect inside SunnyBoy.
75 feet 8AWG (3 conductor stranded with ground) to main disconnect panel. Routed in 1" PVC conduit under front porch.
40amp OCPD inside disconnect panel. (Disconnect Panel has my meter base and 200 amp breaker to "sub-panel" that feeds my house.
TOTAL system cost $13K. With Oregon & Federal incentives of $9.9K the break even should be 3 years.
I am actually looking forward to getting my next power bill....
Patriot install mosaic.jpg


The Patriot Solar Group racking system uses a "C channel" post that is driven 5 feet into the ground. No need for 24" diameter holes filled with concrete. The trusses are attached with 2 bolts and the purlins have another 2 bolts. A very simple design with simple installation. I used a Bosch Brute jackhammer to "pound" the posts and prepared each post location with 5 buckets of water during the preceding 24 hours. Post pounding was about 15 minutes each. Jackhammer was a $60 rental but I had to fabricate the pounding "bit"..
PocoSolarComplete.jpg

Patriot Solar Group includes mounting clips that connect the panels to the racking system as well as provide electrical ground. AHJ was pretty impressed with the simple and clean installation.
performance Oct24.jpg


SunnyBoy monitoring generated the blue plots. I created a composite of generation over 3 days showing 5630 watt peak at mid day. TheSunEarthTools graphic shows Oct 25th in the gold/yellow curve. Sun angle relative to my array set at 35 degrees is about 115 degrees as the sun peaks at 31.12 degrees. My peak generation in Oregon will be when sun angle is at 55 degrees around April 25th and Aug 14th. I'm eager to watch generation in the months ahead. My SunnyPortal is https://www.sunnyportal.com/Template...c-968aaec43d84

Hope this helps someone else. It's not hard to do a solar array with a little planning and some "friends" at www.solarpaneltalk.com

[kb58]

Used string instead of a laser, or is the bow due to gravity?
I'd like to use driven posts like that but our clay/sandstone soil won't take it

[PocoEV]

Rookie mistake using a string that Sir Isaac Newton was yanking on...I didn't think it would make a big difference but had to offset panels down the array. Not a big deal for a "one high" racking system. I was planning to fabricate a story around the focal point of a parabola based on sun angle and latitude. Maybe someone can give me a few pointers....

[AzRoute66]

Clearly it is because in the morning and evening, the elevation of the sun changes at a much faster rate with regard to azimuth than it does during mid-day. The natural logarithm is non-linear.

[bcroe]

A couple lasers have solved a lot of problems around here. Work most times, wash out under
intense noon day sun. Bruce Roe

[Syberdog]

I almost bought the Patriot Delta rack (ballast blocks instead of posts) but they wanted $800 shipping from Michigan so I ended up using their design for the bases of my rack
You really got it in quick. How much DC voltage loss do you have running 300' to the inverter?

[Farlander]

I would have recommended carrying a ground back to the inverter as well. Apparently the 2014 requirement to provide grounding electrode conductors for arrays is bogus and a no no when it comes to lightning protection. According to Mike Holt. Anyone care to comment?

https://www.youtube.com/watch?v=Ypo99VRxT44

Watch @ 7:50

[bcroe]

There is a ground all the way from my meter to the frame of the last panel in my array. It is a safety
ground, so a shorted panel can't put 400VDC on the frame. There are also dozens of grounds directly
under the ground mount, by virtue of the concrete foundation. These I hope will help deal with a
lightning strike. As for my inverters, they are expendable in this situation. Bruce Roe