Once the nominal power of the PV modules to be installed is known and their number calculated, the next design step is to determine how modules will be wired.

By connecting modules in series, their voltages are added. The total voltage will be the sum of the voltage of all single modules. The current remains the same and will be equal to the current of a single module.

If panels are connected in parallel, the current will be equal to the sum of the current of all single panels and, the voltage will remain equal to the voltage of one single panel.

Array configuration is influenced by the system voltage and aesthetic. Usually, system voltage is increased as the total load increases. However, here is what is recommended:

• 12Volts system voltage for energy demand bellow 1kWh ;

• 24Volts for energy demand between 1kWh and 3 to 4kWh;

• 48Volts for energy demand above 3 to 4kWh.

System voltage must correspond to inverter input voltage. In certain cases, inverter's input voltage dictates system voltage.

Modules are first wired in series strings to increase single modules voltage and reach the system voltage, then; strings are wired in parallel to reach the required PV power output.