The post mount for this array is a model 18X built by General Specialties.  It is the largest pole mount available as far as I know.  That's important to me because this is the best spot on my property to locate an array, so I wanted to make the most of it.  It's also more cost effective to install one large array compared to several smaller ones.

The first step is to dig a hole for the 8" schedule 80 pipe.  The hole has to be 9 feet deep and will hold 12 tons of concrete.  Then a trench is dug for the transmission wire conduit.  Getting the conduit in the trench before the concrete makes a much cleaner job.

The next frame shows how valuable it is to have a handy piece of equipment.  The Bobcat proved to be an essential tool throughout the project, as you will see.

The 19' pipe has a 5/8" wall thickness and weighs about 1000 pounds.  It would certainly be worth renting a piece of equipment for this installation.  I was able to complete the entire process single-handed, aside from a friendly assist from my wife now and then

The post was set perfectly on the first attempt.  Never underestimate a little bit of good luck.

A mount this big holds an array measuring 16 feet square.  That means the post has to be at least 10 feet out of the ground to give the ground clearance needed for winter sun angles.

Here is a detail shot of how I rigged the pole so I could carry it vertically with the Bobcat.  The chains were welded to the pole just above the half-way point so it would remain stable during transport.
The wooden clamps keep the chains from slipping on the forks.

A minimum of 8 feet of underground depth is specified for this installation.  I was able to get the hole about 9 feet deep for an extra margin of safety.  As you will see, the mount and panels are both heavy and large, presenting the possibility of heavy wind loading on the structure.  It would be unwise to cut corners on proper anchor depth or size.   This hole will hold about 12 tons of concrete.

I used a cutting torch to make holes through the bottom section of the post, so steel reinforcing bars could be inserted after the post is set in the hole.  This keeps the post well-anchored in the concrete and prevents it from turning under load.

Once the post is set, some arrangement must be made to keep it exactly vertical while the concrete is poured.  I used ratcheting straps to hold four scrap 2x4s to the steel.  This made it easy to secure the four supports with long deck screws.  Remember that the steel pipe weighs nearly half a ton and is very difficult to control by hand if it gets off balance.  This is compounded by the fact that it is in a deep hole and difficult to maintain safe footing around the edge.  I ended up making a sort of temporary scaffold from long pieces of wood and sheet goods to keep the edge of the hole from caving in and filling the bottom of the hole with loose dirt.  I wanted clean concrete all the way to the bottom of the hole.

As seen here, the pipe is very stable and well supported.  This is extremely important because you don't want to have any shifting as all that concrete is poured in the hole.  Don't take any chances you'll regret.

Like magic, the concrete work is done.  In fact, the concrete came on a day when I had to be away from the house.  My brave and capable wife managed the task in my absence.

You may notice that I framed up a simple rectangle around the base of the post.  It looks neater, and provides a little extra weight for the base.  Just as important, it makes a safe place to position a ladder for the rest of the work of assembling the mount and installing the array.

The round portion of the mount is called the thimble, and it simply slips over the end and is secured by the large bolts you see on the side.  The cross piece pivots on two bolts and allows the array to be angled for optimum sun exposure.  This cross piece is the heaviest piece of the array, and all I could manage to get it in place on my own.  Lucky to have the Bobcat to lift it to the top of the pole.

Both arms are now installed on the central tee.  This photo shows how handy it is to have a flat slab of concrete around the base of the pole.

Another example of letting hydraulics do the work for you.  It's important to use a good machine with a reliable hydraulic system that doesn't bleed down.  Always prepare for the possibility that hydraulics could suddenly fail.  Don't put your life in jeopardy!  This step would have required three people without the machine (the steel bars are very heavy).

To install the other cross-bar, I flipped the mount over to the other side.  The mount flips over very suddenly and with force.  This move should be carefully planned.  I did it with the machine forks and was well out of harm's way.

Here you can see that the main frame of the mount is fully assembled.

This mount has a very well designed system for controlling the array angle.  Due to the size and weight involved, a strong mechanism is needed.  Here, I'm installing the upper part of the control system.

The hand winch can be seen attached just to the left of the thimble.

This photo shows the adjustment bar in place.  It is a simple telescoping piece with holes for adjustment.  The winch is used to handle the task of positioning the mount to the proper angle, and the adjustment bar locks it in place with a bolt.

These rails are made from aluminum alloy.  They are the final part of the mount structure, and the solar panels mount directly to holes pre-drilled in the rails.  The rails connect to the steel structure with U-bolts, which allows the rails to be adjusted for different panel sizes.  Good measurement and planning are crucial for correctly positioning the two central rails.  Position the mount horizontally for this step.  Once again the Bobcat proves its worth in making the job much easier.

The outside rails are installed and the panels go in place.  The U-bolts can be left slightly loose until the panels are installed.  This makes it easy to get the rail spacing right.  Don't forget to tighten the U-bolts later!

I installed only two modules on this side to keep the balance of the mount fairly even until the other side is installed.

These ten modules will all connect to the same charge  controller.  The eight modules that will fill the corner positions will connect to another controller.  This part of the array is ready to be connected, and that's just what I did.  I wanted to be making power ASAP!

In this shot, I'm welding a bracket to mount the Outback combiner box.  It is designed to handle two independent circuits, so it is ideal for my use.  You can see that the shadows are getting long.  I'll barely get this array connected before dusk.