Torsion ability is particularly important to wind turbine cables because such cables moves along with wind turbine blades during power generation. If they are not torsion resistant enough and their cores break, wind turbines may break down to incur fires or other accidents. In order to provide such cable, Walsin Lihwa develops wind turbine cable successfully and has obtained patents in Taiwan (patent certificate no. M426854), Mainland China (patent certificate no.201120509692.4), and the U.S. (patent certificate no. US8,729,390 B2). According to the U.S. National Electrical Code, wind turbine tray cables (WTTC) are the power cables that can be installed in wind turbine cable trays or ducts. In the Underwriters Laboratories (UL) certification category of ZGZN, Walsin Lihwa wind turbine cables have been certificated for resistance to cold bending, oils, sunlight, and twisting to meet the UL RHW-2 specifications.