When the sheath of C.T.S. cable made of rubber or some other compound mixed with rubber remains exposed to direct sunlight, arrangement must be provided to cover it up properly. It should, however, be noted that when sunlight comes through the glass of a window,-it is not regarded as direct sunlight.
Where weather proof or lead-sheathed cable is to be drawn with the help of catenary wire, either the cable should be taken by binding it continuously with the catenary wire or it should remain fixed with catenary wire by means of link dips at intervals of about 15 cm.
C.T.S. cable is drawn over the wall in the same Way as lead-sheathed cable. At first wooden plugs are grouted or cemented in the wall at intervals of about 75 cm and polished thin batten of teak wood as wide as or a little wider than the cable is screwed to these plugs. Tinned brass or aluminium link clips are then fixed on this batten with the help of iron pins at intervals not exceeding 10 cm horizontally and 15 cm vertically.
For the sake of convenience of work, sometimes clips are fixed on the batten at equal intervals in a straight line first and then the batten is screwed to the wooden plugs. Finally the cable is laid neatly on the clips which are then folded. In some cases a batten with clipped cable is screwed to the wooden plugs.
From the very beginning one has to decide about where and how many clips should be arranged side by side. The rule is that a single clip may be used to fix upto two twin-core, 0.0194 cm2 cables. If the cross-section of the cable is greater than this, a single clip may hold only one cable.
Where there are fumes from acids etc., clips are made of lead strips cut out from thin lead sheets and iron pins are already painted with acid-proof paint. This prevents the iron pins being rusted when come in contact with acid fumes.
For a neat and clean look of C.T.S. wiring or for saving it from mechanical injury, the wiring may be covered by wooden channelling or any other suitable cover. Also C.T.S. cables may be drawn through conduit pipes, if necessary.
Bend of Cables at Turning in C.T.S. Wiring:
ADVERTISEMENTS:
C.T.S. cables shall never be turned at right angles. Wherever there is a bend, the radius of curvature shall not be less than six times the outer diameter of the cable.
C.T.S. wiring can be used with all sorts of fittings. Moreover, it can also be used in case of concealed wiring. The use of this cable is approved for drawing it through hollow wall or hollow floor. Cables are available as single-core, twin-core or three-core. One of the special advantages of this system is that, wiring can be done very easily and quickly. As a result wiring is economical on the whole, although the cable may cost more.
Wiring through a Floor or a Wall:
While taking through a floor, the cable shall be drawn through a heavy gauze conduit. The two ends of the conduit should be fitted with bushes made of wood or rubber or any other suitable insulating material. The bottom of the conduit should be flush with the ceiling of the lower floor, while its top must rise upto a height of 1.5 m above the floor level of the upper floor.
ADVERTISEMENTS:
As in case of other systems of wiring, porcelain tubes may also be used when the cables are dawn through a wall. Here two single core cables (one live wire and one neutral wire of the same circuit) or a twin-core cable shall be drawn through each conduit. Precaution should be taken to see that there is no turning or bending of cable inside the conduit.
Peeling Off Sheath from C.T.S. Cable:
When internal conductors are to be taken out for connection, the knife is driven into the sheath with such a great care as not to injure the rubber insulation of individual conductors even to a little extent. The length of the cable to be peeled off should be such as the cable must reach as near the connector as possible.
After completion of wiring one should not hit the clips with metallic hammer. If painting is necessary, it should be done last. At first a thick priming coat without oil is applied. On to this coat oil-free paint or distemper for use on wall may be used.