Mounting and Grounding
I recommend mounting solar panels onto 2 aluminum rails. Place the aluminum rail against the stainless steel bolts, hammer the rail, then flip the rail over; you’ll now see the drill locations needed.
I’ve also used UniRac’s SolarMount modular mounting system; I purchased 2 rails and 2 tilted legs to create a ground mount system that can also be used on a flat roof. Drill holes in the rails to match the mount on the UniRac mount system.
It’s recommended to orient solar panels toward due south. Simple enough. You also want to angle your solar panel perpendicular to the sun. However, the sun follows the azimuth angle throughout the day — the greatest charging potential is during solar noon — and the sun’s angle changes not only throughout the day, but also throughout the year.
If you’re going to mount the solar panel in a fixed position, a good rule of thumb is as follows. If you are off-grid, mount the solar panel for latitude plus 15 degrees. Winter is the season that’s most critical for off-grid homes, because of the lack of sunlight.
If you have a grid-tie setup, mount the solar panels for latitude minus 15 degrees. This orientation will increase your generation during summer months, when you can sell more power back to the grid, or use it for air conditioning.
If your solar mounting system is adjustable, adjust the panels at least 4 times a year, bringing them (roughly) perpendicular to the sun angle at solar noon. Go here
to see tools related to the solar path for your particular latitude.
According to the National Electrical Code, all solar panel systems need to be grounded to code. I recommend reading the NEC handbook for detailed information regarding electrical codes. At a minimum, the NEC requires that all systems must have equipment-grounding conductors that connect the metal surfaces of the solar panels to a ground rod. My grounding system consists of the following items:
- Two code-compliant ground lugs screwed into each aluminum rail that touches the solar panel.
- An 8-foot grounding rod driven into the earth near the solar panel array.
- 6-gauge stranded copper wire (preferred) or solid wire connected to the ground lug and then to the ground rod.
Also read John Wiles’ article, “To Ground or Not To Ground: That Is Not the Question (in the USA),” available here
In the next volume of MAKE, I’ll show you how to connect the solar panel to your electrical system. For now, check out the image above for a visual overview of the electron flow in a typical solar system.