(1) An overhead line shall not cross over an existing building as far as possible and no building shall be constructed under an existing overhead line.
(2) Where an overhead line of voltage exceeding 650 V passes above or adjacent to any building or part of a building it shall have on the basis of maximum sag a vertical clearance above the highest part of the building immediately under such line, of not less than, –
(i) for lines of voltages exceeding 650 V and up to and including 33 kV - 3.7 metre;
(ii) for lines of voltages exceeding 33 kV - 3.7 metre plus 0.30 metre for every additional 33 kV or part thereof.
(3) The horizontal clearance between the nearest conductor and any part of such building shall, on the basis of maximum deflection due to wind pressure, be not less than, –
(i) for lines of voltages exceeding 650 V and up to and including 11 kV - 1.2 metre;
126 THE GAZETTE OF INDIA : EXTRAORDINARY [PART III—SEC.4]
(ii) for lines of voltages exceeding 11kV and up to and including 33 kV - 2.0 metre;
(iii) for lines of voltages exceeding 33 kV - 2.0 metre plus 0.3 metre for every additional 33 kV or part thereof.
(4) For high voltage direct current systems, the vertical and horizontal clearances, on the basis of maximum deflection due to wind pressure, from buildings shall be maintained as below:
Sl. No. High Voltage Direct Current Vertical Clearance (metre) Horizontal Clearance (metre)
1. 100 kV 4.6 2.9
2. 200 kV 5.8 4.1
3. 300 kV 7.0 5.3
4. 400 kV 7.9 6.2
5. 500 kV 9.1 7.4
6. 600 kV 10.3 8.6
7. 800 kV 12.4 10.7
(5) The vertical and horizontal clearances shall be as measured as illustrated in Schedule VIII C.
Explanation. – For the purposes of this regulation, the expression “building” shall be deemed to include any structure, whether permanent or temporary.