| 摘要 |
PURPOSE:To prevent electrolytic corrosion without need for connection work between the electrode and the cable core wire by using for the electrode a part of a core wire coated with a semiconductive layer after the insulation layer is removed therefrom. CONSTITUTION:A multi-core cable for transmission uses a cable 30 with a sag in which core wires 40 are put together by an alternately inverted twisting at a short pitch. The core wires 40 employ a conductor 400 onto which a semiconductive layer 402 and an insulation layer 404 are extruded doubly. The cable 30 thus obtained is installed underground along an oil tube 10 and different core wires 40 are drawn out with a sag sequentially at specified intervals. The core wires thus drawn out are used for electrodes 21... by removing the insulation layer 404 by a proper length. One end of the multi-core cable 30 is connected to a detector section 50. |
