Precautions to be Taken Wooden Casing and Capping Wiring

Precautions to be Taken Wooden Casing and Capping Wiring Points : precautions to be taken wooden casing and capping wiring

1. The casing must be kept at least 3.2 mm apart from the walls or ceilings by means of porcelain distance pieces of thickness not less than 6.5 mm in order to keep the casing dry at the back.
2. All cappings, should be attached to the casings (after all insulated wires are laid inside grooves) by round head screws (preferably of brass) fixed on edges and screwed to the outer walls of the casing at an interval not exceeding 15 cm cross-wise (i.e., 30 cm between two successive screws on each side) for all sizes upto 64 mm casing and capping; for size above 64 mm similar additional round-head screws should be fixed on the centre wall (or alternative walls in case of 3 grooves) at an interval of 45 cm.
3. While screwing capping over the casing precautions should be taken that screws go into the dividing wall of the casing otherwise they will damager the cable insulation.
4. The casing and capping should be painted with the paint as specified in I.S. 732 before erection. It is also to be painted or varnished to give desired finish after erection. The precautions No.8, 12 and 13 stated with cleat wiring system are also to be observed.
5. The wooden gutties on which the casing is screwed must be fitted into walls or ceilings at an interval not exceeding 90 cm for sizes of casing capping up to 64 mm and not exceeding. 60 cm for sizes more than 64 mm.
6. The joint whenever required should be made with good workmanship and in approved manner.
7. The casing-capping used Should be of first class seasoned straight, smooth and hard teak wood.
8. The casing should be well fixed to its supporting structure i.e., walls or ceilings.
9. At bends the grooves must be rounded off in order to save insulation from damage.
10. In no case the cables of opposite polarity should he run in one groove.
11. Gaps should be avoided.