Basic Electrical Installation Work

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excessive vibration expected the cable should termi- nated conduit through box and the final connection made flexible conduit. When bending cables the radius the bend should not cause the cable become damaged and clips should provide adequate support (Regulation 522. The cable must prepared for termination removing the outer copper sheath reveal the copper conductors. This makes the cop- per outer sheath stiff and may result fracture. All excess magnesium oxide powder must wiped from the conduc- tors with clean cloth. Connection cables can made directly motors, but absorb the vibrations 360° loop should made the cable just before the termina- tion. This can achieved using a rotary stripper tool or, only few cables are terminated, the outer sheath can removed with side cutters, peeling off the cable simi- lar way peeling the skin from piece fruit with knife. reduce the risk dam- age the outer sheath during installation, cables should straightened and formed hammering with hide hammer block wood and a steel hammer. Cable ends must terminated with special seal prevent the entry of moisture. 14. The outer sheath the cable must not penetrated, otherwise moisture will enter the magne- sium oxide insulation and lower its resistance. This prevent moisture from penetrating the seal capillary action. The cable diameter small relation its current carrying capacity and should last indefinitely correctly installed because is made from inorganic materials.4. Figure 6. The cable can be work hardened over-handled over-manipulated.3 shows brass screw-on seal and gland assembly, which allows termination the cables standard switchgear and con- duit fittings. When enough conductor has been revealed, the outer sheath must cut off square to facilitate the fitting the sealing pot, and this can done with ringing tool. These characteristics make the cable ideal for Band emergency circuits, boiler-houses, furnaces, petrol stations and chemical plant installations.Basic Electrical Installation Work 318 The cable may laid directly the ground, ducts, cable tray or clipped directly structure.5. The sealing pot filled with sealing compound, which is pressed from one side only prevent air pockets forming, and the pot closed crimping home the sealing disc with crimping tool such as that shown Fig 7. Such assembly suitable for working tempera- tures 105°C. The cable supplied coils and should run off during installation and not spiralled off, described Fig.26 for conduit. The conductors are not identified during the manufacturing process and so necessary identify them after the ends have been sealed.8. not affected water, oil the cutting fluids used engineering and can withstand very high temperature or even fire.5), see Table 14. Other compounds powdered glass can increase the working temperature 250°C. simple continuity polarity test, described later this chapter, can identify the conductors which are then sleeved identified with coloured markers.