The cables used in the low-voltage DC transmission part of the solar photovoltaic power generation system have different requirements for the connection of different components due to different usage environments and technical requirements. The overall factors to be considered include the insulation performance, heat resistance and flame retardancy, aging resistance, and wire diameter specifications of the cables. The specific requirements are as follows: 1. The connecting cables between solar cell modules are generally directly connected using the connecting cables attached to the module junction box. If the length is not enough, special extension cables can also be used. According to the different power levels of the components, this type of connecting cable has three specifications: cross-sectional area of 2.5m ㎡, 4.0m ㎡, and 6.0m ㎡. This type of connecting cable uses a double-layer insulation sheath, which has superior resistance to UV, water, ozone, acid, and salt erosion, superior all-weather capability, and wear resistance. 2. The connecting cable between the battery and the inverter requires the use of multi strand flexible wires that have passed UL testing, and should be connected as close as possible. Choosing short and thick cables can reduce system losses, improve efficiency, and enhance reliability. 3. The connecting cable between the battery array and the controller or DC junction box also requires the use of multi strand flexible wires that have passed UL testing, with the cross-sectional area specification determined by the maximum current output of the array. The cross-sectional area of the DC cable in the designated area is determined based on the following principles: connecting cables between solar cell modules, connecting cables between batteries, and connecting cables for AC loads. Generally, the rated current of the selected cables is 1.25 times the maximum continuous working current of each cable; The connection cables between solar cell arrays and between batteries (groups) and inverters are generally selected with a rated current of 1.5 times the maximum continuous operating current of each cable.