Which temperature is used for the cable sizing?

When sizing string cables (fastened to the structures), pvDesign considers the maximum temperature of the TMY as the temperature to size this group of cables, and it also considers that the PV module is working at its maximum capacity. This way, it ensures that the cable can withstand any heating or module working conditions. If the cable is directly buried in a trench, the ground temperature defined by the user (in the “Electrical” tab) is the one considered to size these cables.