GB917051A - Improvements relating to terminal boxes for electrical apparatus - Google Patents

Abstract

917,051. Junction-boxes. ASSOCIATED ELECTRICAL INDUSTRIES Ltd. Jan. 27, 1961 [Jan. 28, 1960], No. 3141/60. Class 38 (1). A terminal box comprising a metal casing 1 having rear and bottom cable openings 5, 4, a front access opening 3 and a flange 6 for attaching it to high-power apparatus M, has a box-like insulating lining 2 within which are joined cables 16, 17, passed through openings 5, 4, and glands 15, 19, in the lining wall. The lining has a front opening corresponding to access opening 3, both openings being closed, as shown, by a cover 8 lined with insulation 2<SP>1</SP> or alternatively a separate insulating lid may be fitted to the lining. The rear wall of lining 2 slopes forward to provide an expansion space B which helps to reduce the external effect of an explosion due to any electric fault; also a frangible panel may be secured over the opening 5 (Fig. 3, not shown) so as to explode towards the apparatus M. For multi-phase use the box may be divided into several compartments, one for each phase, by steel partitions welded to the inside of the casing (Fig. 2, not shown), each compartment having an insulating lining. The cable connections 18 may be enclosed by insulating tape 20 or the whole internal space may be filled with silicone elastomer putty. A multicore supply cable may be brought into a sealing-box (Figs. 3, 4, not shown) attached to the box below opening 4, the cores being connected to cables 16 by short interconnectors. The sealing box is partly filled with sealing compound and may be provided with humidity indicators and dessicators, e.g. of the silica gel type, if desired. In this construction the phase separating partitions extend through the casing 1 into the sealing compound, thus improving the inter-phase insulation between compartments of the multi-phase box.