A site evaluation is the first step towards installing a photovoltaic (PV) solar array anywhere in the world. Every array needs to be a customized in order to maximize power generation while balancing customer goals. There are many variables that get factored into our customized designs and we need to be as accurate as possible to guarantee our work. Starting with each customer’s electric bill, we will determine what percentage of the annual electric bill can be offset. An exposure analysis with a pathfinder will give us the exact position of sun throughout each day and year in relation to the proposed location of the array. By averaging these positions along with the sun’s apparent location east/west of true south, and pitch of the proposed area, we can determine each location’s potential power production. This information is compared to the electric bill and used to determine the amount of electricity that can be offset by the PV system. To generate the maximum amount of power from the sun at any location, the sun’s rays need to hit the face of the solar panels at 90 degrees for as long as possible throughout the day. This is more easily attained when the roof is facing solar south at 180 degrees magnetic. The material, slope, and age of the roof also play a significant role in designing a solar system for the same reasons. The roof must be structurally strong enough to bear both the load of the system mounted on the roof and withstand uplift forces. The type of racking used to hold down the panels is mainly dependent on the material/type of roof that exists (asphalt shingles, standing seam, slate, EPDM, etc.). If the roof is old enough where it will need to be replaced in the near future, that should be done before installing the array as will have to be removed in order to replace the roof beneath the array. There are also several electrical design factors that we consider in the design. There are essential electrical components (inverters, meters, AC/DC disconnects, etc.) that must be mounted in compliance NEC code. Other electrical issues include looking for the most efficient way to run wires from the panels to the inverters, how to electrically tie the system into the customer’s existing utility grid. All of these factors are included when designing the size of each solar system and choosing what products to use within those systems.