Note: The information contained in this periodical weblog may be outdated. This was my personal weblog published before January 1, 2015. Since then I have been the co-owner and Principal Solar Designer at Florida Solar Design Group.

Building a Ground Rack Solar Electric System

We’re working on a solar energy project in Alva, FL. The first thing my customer said when he saw his ground rack for the 11kW solar electric systems was, “Wow, it’s big!”

Solar Panel Ground Rack
Solar Panel Ground Rack

I responded, “No, it’s powerful!”

The truth is, ground racks for solar panels can be quite robust, especially in Southwest Florida where required design wind loads can be as high as 150 mph.

This particular system is a Unirac U-LA (Large Array) design using 3 inch galvanized steel pipe and 3 inch square aluminum tubing for the main substructure. The solar panels will sit atop Unirac HD rails and will be bottom clamped for a clean and attractive look from the front.

The foundation for the system is a concrete footing and slab requiring 11 cubic yards of fiber reinforced concrete (just over one full cement truck) and steel rebar in a continuous footing. In other words, it’s a serious structure! In typical Fafco Solar fashion, we exceeded the engineering requirements, adding over 1.5 tons of extra concrete and embedding columns over six inches deeper than required.

Solar Ground Rack Footing Detail
Solar Ground Rack Footing Detail

Once the extruded aluminum rails span the horizontal pipes, the whole integrated structure will be extremely strong – enough to handle any reasonably expected winds.

This utility interactive photovoltaic system will be comprised of 48 Canadian Solar 230W black framed modules and 48 Enphase M215 microinverters, and has a DC system rating of 11.04kW. This system will significantly reduce this homeowners utility bill. Performance will be tracked online with the Enphase Enlighten Web Monitoring system.


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