The most commonly used wire gauge connecting solar panels is 10 AWG. Why 10-American-Wire-Gauge (AWG) is selected as the standard for external connection of solar arrays due to the following: Consider water flowing through a hosepipe. This guide aims to address the questions and issues related to solar cables, their classification, and functions, and technical. . Which cable is best for a solar panel? In a solar power system, the cable may seem like an inconspicuous connecting component, but it is actually crucial to the system's performance—it transmits the DC power generated by the photovoltaic panels, directly impacting power generation efficiency. . When installing solar panels, using the right solar cable is critical for safety and efficiency.