Control cable fault line common mechanical damage, damage to insulation, wet insulation, insulation aging and deterioration, over-voltage, cable overheating fault and so on. When the failure occurs when the line should be cut off the power supply cable fault, find fault, the fault inspection and analysis, and repair and testing, the cut off of the cut off until the fault is removed only after the restoration of electricity.
　　Control cable electrical performance of the main
　　1 DC Resistance: 20 ℃, 0.4mm copper, less than or equal 148Ω/km, 0.5mm copper, less than or equal 95Ω/km.
　　(2) Electrical Insulation strength: no breakdown 1min 1kv between conductor and shield conductor breakdown 1min 3kv not
　　3 Insulation resistance: each core wire line with the rest of the ground, control cable than 10000MΩ.km, HYAT cable than 3000MΩ.km.
　　4 Working capacitance: mean 52 ± 2nF/km
　　5.Control cable FEXT defense degree: 150kHZ combination of power when the average is greater than the specified 69dB/km.