A 8
[Subsidiary]
line conductors crossing other lines:
Supports;
L.N. 236/72.
factors of safety of supports:
CAP. 103]
Electricity Supply Regulations
[1984 Ed.
(5) Where a line conductor crosses over or under or is in proximity to any other overhead wire, precautions shall be taken by the company to prevent contact, due to breakage or otherwise, between the line conductor and the other overhead wire, or between the other wire and the line conductor:
Provided that this paragraph shall not be deemed to require the company to take precautions against contact between a broken line conductor and other auxiliary conductors and earth wires carried on the same support and forming part of the same overhead line.
(6) Line conductors shall be attached to suitable insulators carried on supports of iron, steel, reinforced concrete or wood. Special precautions shall be taken to prevent the corrosion of all metal work at or below the surface of the ground.
(7) The supports, in conjunction with stays or struts if provided, shall withstand the longitudinal, transverse and vertical loads due to the wind pressure hereinafter specified without damage and without movement in the ground. In no case shall the strength of a support in the direction of the overhead line be less than one-quarter the required strength in a direction transverse to the line.
The following factors of safety shall apply to each support-
Factor of safety
Material
Iron or steel
3
L.N. 236/72.
service lines.
L.N. 16/82. L.N. 298/82.
erection of line conductors at different voltages on same supports:
L.N. 76/82. L.N. 298/82.
inspection and
maintenance of lines:
Material Factor of safety Reinforced concrete 4 Wood 3These factors of safety shall be calculated on the assumption that all line conductors, cables and wires carried by the supports are at a temperature of 70°F., and that together with the supports they are subjected to a wind pressure of 40 lb. per square foot.
(8) Service lines shall be connected to line conductors at a point of support only and shall be fixed to insulators on consumers' premises. Every part of a service line (other than a neutral conductor connected with earth) which is accessible from a building with the use of a ladder or other special appliance shall be efficiently protected either by insulating material or by other means approved by the Director of Electrical and Mechanical Services.
(9) Where line conductors forming parts of systems at different voltages are erected on the same poles or supports adequate provision shall be made to guard against danger to linesmen and from the lower voltage system being charged above its normal voltage by leakage from or contact with the higher voltage system; and the type of construction shall be subject to the prior approval of the Director of Electrical and Mechanical Services.
(10) Every overhead line, including its supports and structural parts, and electrical appliances and devices belonging to or connected therewith, shall be regularly inspected and efficiently maintained.