CAP. 103]
[r. 13 cont.]
Factor of safety of line conductors.
Minimum height of conductors.
Electricity Supply.
All stay wires other than those which are connected with earth by means of a continuous earth wire shall be insulated to prevent danger from leakage. For this purpose an insulator shall be placed in each stay wire at a height of not less than 10 feet from the ground.
B. For voltages exceeding 650 volts direct current and 325 volts alternating current.
(15) 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.
(16) The height from the ground of any line conductor at any point on the span at a temperature of 160° F. shall not, except with the consent of the Director of Public Works, be less than the height hereunder stated—
Voltages not exceeding 66,000 volts
20 feet.
Voltages exceeding 66,000 volts and not exceeding 110,000 volts
21 feet.
Voltages exceeding 110,000 volts and not exceeding 165,000 volts
22 feet.
Voltages exceeding 165,000 volts
23 feet.
Provision to prevent danger.
The height from the ground of an earth wire or auxiliary conductor shall not be less than the minimum heights prescribed in paragraph (13) above.
(17) Adequate means shall be provided to render any line conductor dead or harmless to human beings or animals in the event of it falling, due to breakage or otherwise.
All metal work other than conductors shall be permanently and efficiently connected with earth. For this purpose a continuous earth wire shall be provided and connected with earth at four points in every mile, the spacing between the points being as nearly equidistant as possible, or alternatively the metal work shall be connected to an effective earthing device at each individual support. The design and construction of the system of earth connexions shall be such that when contact is made between a line conductor and metal connected with earth the resulting leakage current shall not be less than twice the leakage current...
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CAP. 103]
[r. 13 cont.]
Factor of
safety of line conductors.
Minimum height of conductors.
Electricity Supply.
All stay wires other than those which are connected with earth by means of a continuous earth wire shall be insulated to prevent danger from leakage. For this purpose an insulator shall be placed in each stay wire at a height of not less than 10 feet from the ground.
B. For voltages exceeding 650 volts direct current and 325 volts alternating current.
(15) 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.
(16) The height from the ground of any line conductor at any point on the span at a temperature of 160° F. shall not, except with the consent of the Director of Public Works, be less than the height hereunder stated—
Voltages not exceeding 66,000 volts
Voltages exceeding 66,000 volts and
exceeding 110,000 volts
20 feet.
not
21 feet.
Voltages exceeding 110,000 volts and not
exceeding 165,000 volts
22 feet.
Voltages exceeding 165,000 volts
23 feet.
Provision to prevent danger.
The height from the ground of an earth wire or auxiliary conductor shall not be less than the minimum heights prescribed in paragraph (13) above.
(17) Adequate means shall be provided to render any line conductor dead or harmless to human beings or animals in the event of it falling, due to breakage or otherwise.
All metal work other than conductors shall be per- manently and efficiently connected with earth. For this purpose a continuous earth wire shall be provided and connected with earth at four points in every mile, the spacing between the points being as nearly equidistant as possible, or alternatively the metal work shall be connected to an effective earthing device at each individual support. The design and construction of the system of earth connexions shall be such that when contact is made between a line conductor and metal connected with earth the resulting leakage current shall not be less than twice the leakage cur-
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