GB200895A - Improvements relating to the connection of electric cables to electrical apparatus - Google Patents

Abstract

200,895. Holt, F. B., and Metropolitan- Vickers Electrical Co., Ltd. April 19, 1922. Cable couplings; earth-continuity couplings; junction-boxes.-In connecting an armoured lead sheathed cable to a junction box or entry box or the like a gland, projecting through the orifice in the wall of the box, is secured to the lead sheath the cable armour being secured to a second gland fastened independently outside the box. In one construction a trifurcating box, Fig. 1, longitudinally divided, has its end wall 12 extended transversely to the cable and an orifice 13 in it is wholly or partly surrounded by an internal boss 14. The cover portion 11 has an end wall lying within and against the end wall 12 of the base portion and a semicircular notch holds a gasket 16 to make joint with the boss 14. A gland 17 of considerable length is made a sliding fit on the cable sheath 27 and is secured in the orifice 13; a wiped joint is made between the outer end and the cable sheath. A divided sealing chamber 19 may be secured to the box about this joint. The armour wires are clamped between conical glands 23, 25 which may be secured to the sealing chamber and earthing connections are made by wires 26. Where a wiped joint is not practicable or desirable the lead sheathing may be cut into strips 32, Fig. 6 which are secured between the gland 17 and a co-operating gland 33 mounted on studs screwed into the end wall 12 of the box, an expansion space being left between the end of the gland and the bends of the strips. All strain upon the cable is taken in both constructions by the armour clamp. The box and sealing chamber are filled with sealing material. The invention is applicable generally where a cable passes into or through a partition or wall of a casing.