Step out away from the building about 12-16" and drive the ground rods down spacing them at least 6' apart. If you hit something deep, dig a trench about 12" deep, bend the rod over and then bend it back up at the end so the top of the rod is flush with grade (making a big offset). The code says there needs to be 8' buried in the ground , it doesn't have to be straight up and down. Connect everything together with one continuous piece of #6 Solid Copper from the Ground Bar to the furthest rod. Leave the ground clamps at the top of the rod exposed for the inspector to see...it's ok to cover everything in between.
Also, make sure you have a separate Ground Bar and a non-bonded Neutral Bar at the garage panel...do not install the Bonding screw or lug that comes with the panel, you only do that at the Main Service (next to the meter).
Mike B
