导体标秤截面2导体中单线最大直线mm覆盖层总厚度规定值mm复合覆盖层中的护套厚度规定值mm平均外径20℃时导体最大电阻20℃下限mm上限mm镀锡单线Ω/km未镀锡单线Ω/km160.212.01.39.211.51.191.16250.212.01.310.513.00.7800.758350.212.01.311.514.50.5520.536500.212.21.513.517.00.3900.379700.212.41.615.519.50.2760.268950.212.61.718.022.00.2040.198