1984 Ed.]
Electricity Supply Regulations
[CAP. 103
(11) All materials used shall at the time of erection conform to the specifications for the time being in force of the British Engineering Standards Association and the Post Office (London) for the construction of aerial lines, so far as the same are applicable and are not inconsistent with this regulation.
PART II
SPECIFIC
(Applicable according to the voltage between line conductors where no part of the system is connected with earth, or according to the voltage to earth where part of the system is connected with earth.)
A-For voltages not exceeding 650 volts direct current
and 325 volts alternating current
(12) The factor of safety of line conductors shall be 2. The factor of safety shall be based on the breaking load and shall be calculated on the assumption that the line conductors are at a temperature of 70°F. and that they are subjected to a wind pressure of 40 lb. per square foot.
(13) The height from the ground of any line conductor (other than a service line), earth wire or auxiliary conductor at any point of the span at a temperature of 160°F. shall not, except with the consent of the Director of Electrical and Mechanical Services, be less than 19 feet across a public road or 17 feet in other positions. A height of 15 feet may be adopted in situations inaccessible to vehicular traffic.
Where a service line is carried across or along a carriage-way, the height of the line from the ground at any part of the carriage-way shall not, except with the consent of the Director of Electrical and Mechanical Services, be less than 19 feet and 17 feet respectively.
(14) Where the voltage to earth exceeds 250 volts direct current or 125 volts alternating current, precaution should be taken to prevent danger,
(I) from a broken line conductor by the provision of- (a) a neutral or earthed conductor carried continuously from pole to pole, and so arranged in relation to the other conductors that in the event of breakage of any one of them the line conductor shall make contact with the earthed wire; or
(b) other means approved by the Director of Electrical and Mechanical Services;
(II) from leakage by the provision-
A 9
[Subsidiary]
materials used.
factor of safety of line conductors;
minimum height of conductors:
L.N. 76/82. L.N. 298/82.
L.N. 76/82. L.N. 298/82.
provision to prevent danger;
L.N. 76/82. L.N. 298/82.
(a) in cases where metal poles are used, of-
(i) an earthed wire, running from pole to pole and connected to the poles; or