GB1195524A - Slip-On Power Cable Termination with Improved Entrance System - Google Patents

Abstract

1,195,524. Cable terminations. G. & W. ELECTRIC SPECIALTY CO. 7 Jan., 1969, No. 973/69. Heading H2E. A fluid-filled terminator for the end of a shielded power-cable comprises a tubular ceramic member 11, cemented to a metal base 15; a metal hood 22, fitted in a cap 20 over the top of the ceramic member 11; an internally threaded ring member 23 soldered in the hood 22; a bolt 60 fitting in the ring 23; and an entrance plate 32 secured to the base 15, serving to hold in position an apertured elastomeric diaphragm 34 and plastics film seal 35. The cable end is stripped of insulation and covered with a connector 31 which is inserted through the diaphragm 34, seal 35, and base 15, so causing rupture of the seal, contact being made by the connector 31 to the bolt 60 and thus to a lug 61 for external connections. An earthing connection to the cable shield 28 is made by a closed annular earthing ring 36, with depending resilient fingers 37 and legs 38 which are riveted to the base 15; there also being an elastomeric boot 42 and container 43 to minimize pressure differentials between the earthing contact system and the outside environment. The earthing ring 36 is preferably of copper or beryllium copper. The top of the device is sealed by a gasket 21; the connector 31 may be pressed, crimped, or soldered to the copper wires 26 of the cable; the filling fluid is preferably a mixture of high molecular weight polybutenes and low molecular weight polyolefins; the diaphragm 34 is preferably made of a silicone or fluorinated elastomer, and the aperture therein is of smaller diameter than the cable, so that a tight seal is established. Before the cable end is inserted a removable cap (24, Fig. 2, not shown) is removed, and replaced by a reservoir (51, Fig. 4, not shown) which receives displaced fluid. When the cable is fully inserted, the bolt 60 is placed in position, together with the sealing plate 58 and resilient gasket 57. Also before insertion, a grounding strap 44 and garter spring 45 are applied to the cable shield 28, after which the elastomeric boot 52 and housing 43 are applied. The strap 44 is of a soft metal such as copper, and has a lug 46 containing a hole in which is inserted a self-tapping screw 48 for connection to the plate 32. Positioning of the spring 45 is aided by spaced protuberances 50. The edge 52 of the boot 42 resides in a groove in the plate 32, and the container 43 is secured to the plate by bolts 55, so compressing the edge 52 to form an hermetic seal. The boot semi-collapses if a reduced pressure develops inside it, so minimizing the pressure differential. A sponge 63 is present in the base 15, and compensates for thermal expansion of the filling compound and/ or the cable insulation.