Specifications

175
NLUO PMC CONTRACTOR
SIGNATURE AND SEAL SIGNATURE AND SEAL SIGNATURE AND SEAL
TECHNICAL SPECIFICATION FOR EARTHING INSTALLATION
The installation shall generally conform to I.S. 3043-Indian Standard Code of practice for Earthing, as amended upto date.
1. Earthing Electrode :
The earthing electrode shall be galvanized steel pipe of class B medium quality 50 mm (2”) dia bore and 3.04 M (10”) long. A
hole shall be provided at 100 mm (4”) from the top end to receive a 13 mm (1/2”) dia galvanized bolt and the bottom end shall
be chisel cut for easy penetration into soil.
A suitable trench shall be excavated about 0.45 M (1”-6”) deep and the pipe electrode driven to an average depth of 3.35 M
(1”-0”) below ground level. The top end of the electrode shall be at an average depth of 3.30 M (1”) below the ground surface.
Alternate layers of Charcoal or Salt and coke to be provided for Electrode as per I.S. code of Practice unless specified
otherwise.
One No. SWG G.I. wire (unless otherwise specified) shall be connected securely on the properly cleaned surface at the top end
of pipe electrode by means of a 100 mm (4”) long x 13 mm (1/2”) dia G.I. bolt nut and double washers. The earth lead
conductor shall be protected mechanically be means of a continuous length of G.I. pipe (Class A) having 13 mm (1/2”) inside
diameter upto a height of 0.60 M (2’) above ground and the same shall be completely filled with bitumen compound and
topped upto overflowing.
2. Masonry Inspection Pit :
The inspection pit for the earth station shall be approx 0.56 M x 0.56 M (1’-10” x 1’-10”) outside dimensions and approx. 0.45
M (1’-6”) deep when completed, having 5” thick cement brick work with 1
st
class bricks in cement mortar (6 : 1) both inside
and outside plastering 19 mm (3 / 4”) thick and neatly cemented 1.60 mm (1 / 16”) thick, both inside, outside and top. The
opening on top shall be provided with a C.I. ring with lockable cover fixed flush with ground surface.
All the excavations shall be duly back filled, dressed and rammed.