The two strings of solar panels shown were connected to assure that each string has complete sun exposure during a specific period of the day. In the morning shade moves out of the roof from left to right so the leftmost panels have full sun exposure before the right panels as is the case in this installation. The layout shown will produce higher power sooner than if each row was a string. A good rule of thumb when deciding the grouping of solar panels is to choose the group that has sun exposure or lack of sun exposure together. The limit to the number of strings is dictated by the inverter and its MPPT specifications.
The complete Solar System Design outlined here was designed by a colleague. The permit was obtained from the County of San Mateo and approved by the local Fire Department . The installation was also done by my colleague and friends and it was approved after an inspection by the Fire Department and the Building Department of the County of San Mateo, California , USA. The design is offered free of charge to anyone who wishes to apply for a permit and feels competent enough to safely handle such a project. However all those who want to do the project on their own should first check their County's required qualifications for the applicant. Please obtain the appropriate County documents for permit application. All the components shown in the diagram on the right are fully documented in the links below and are available online. They may be replaced by other vendors. Preference was given to products manufactured in North America. Two documents, Inverter Line Tapping Specifications and Inverter OCPD Specifications are included to comply with the Application's requirements. There are also requirement on the space needed around the solar panels in order to allow access to the roof for the Firemen. Ask your local fire department for access requirement before planning the solar system In the Installation of Solar Panels' drawing a 3 ft space is shown.
The structural integrity of the roof is also important. Most County Building Departments have the building information on file but if they do not, you may have to provide more than a picture and a drawing as shown here.
The AC junction box has to be able to accommodate two additional fuses and its wiring to the electrical company power meter must be compatible with the power generated by the inverter (both voltage and current). Should this not the be the case , a permit may not be issued unless a new AC junction box is installed by a qualified electrician.