It is often beneficial to over-size the cross-section of electricity cables compared to the standard values that follow out of voltage and current calculations. In the large majority of cases, oversizing has a positive influence on the Life Cycle Cost of the installation. The investment in larger cable is easily paid back by the reduction of Joule losses inside the cable and the subsequent savings on electricity bills.
When the cable is part of a photovoltaic (PV) installation, the investment in a larger-than-standard cable is paid back even faster than in other installations. This is because the allocated electricity price for a PV installation is higher than the market price thanks to the feed-in tariff or green certificates. In other words: the energy losses that are avoided in a PV installation lead to an even bigger financial reward than in other installations.
Increasing the cable cross section in PV installations also creates additional technical and environmental benefits.