... 5mm2, 0.75 mm2, 1.0 mm2, 1.5mm2, 2.5 mm2, 4.0 mm2, 6.0 mm2, 10 mm2, ... , the rated voltage of system should lower then 1.5 times as high as rated voltage of cable and wires ... And the laying temperature should higher then 0°C. Nominal section(mm 2 )Number/diameter of core(mm)Maximum outer diameter ... resistance at 20°C≤(Ω/km)copperaluminumaluminumcopper1.5(A)1/1.383.320.3----------12.11.5(B)7/0.523.521. ...