| 摘要 |
1323696 Cable joints ELECTRICITY COUNCIL 5 Oct 1970 [13 Oct 1969] 50148/69 Heading H2E Relative movement between the core and sheath of a main cable 20 is allowed for in its connection with a secondary cable 21 by having a flexible portion in the connection between the cores of the main and secondary cables, an inner casing 10 surrounding the connection and containing an electrically insulating but thermally conductive medium which does not impede relative movement, and an outer casing 30 being filled with a sealing material. As shown in Fig. 1 the flexible portion is the stranded copper wire core 23 of the secondary cable 21 which passes through a slot 36 in the conductive aluminium sheath 29 of the main cable 20. An insulator 12 is assembled in the core 23 and supports it where it emerges from its connection with an aluminium core of cable 20. A loop of the core 23 passing round the main cable provides flexibility. The connections are soldered, welded, friction welded, or crimped. The inner casing 10 is sealingly clamped to the sheath 29 of main cable 20 and has an aperture for the sealed entry of cable 21. The stranded outer conductor 22 of cable 21 is connected to sheath 29 and, by way of a T-connecting piece, is connected by a flexible conductor 25 to the easing 10, Figs. 5, 6a and 6b, not shown. Casing 10 is filled with oil or grease. The outer casing 30, of metal or plastics, is filled with self or heat-cured resin, hot or cold-poured bitumous material, or thermoplastic material. To internally seal off the secondary cable 21 the bared and opened-out core and sheath strands, Fig. 3, are separated by a cylindrical insulator 14, the interstices between the strands of the conductors being filled with an initially liquid self-curing or heat-setting resin or a bitumous material. Soft putty or mastic tapes, or thermoplastic or hot melt adhesive tapes, may be threaded between the strands and be compressed together to form a hermetic seal. Pressure may be applied manually or by an elastic or heat shrunk sleeve. Instead of introducing end portions of the secondary cable 21 inside the casing 10, separate flexible conductors may be used within the casing between connections with the main cable and terminals mounted on the casing 10, Fig. 7, not shown. The cable 21 is connected to the terminals where they emerge outside casing 10 into casing 30. |
