PROVISION OF CHEMICAL EARTHING GRID FOR LLTR OPS AT AF STATION KUMBHIRGRAM 3RD CALL

Amount

Supply, Installation and testing waterless and maintenance free chemical earthing (grounding) electrode of dia 85 mm x Length 3000 mm with 16 mm Copper bonded MS conductor and Pre cast or cast in situ in high purity electrically conductive granular single make, having ultra low resistivity of 0.001 Ohm - m. ( Provide the resistivity certificate for the same) Electrode made of electrically conductive granular mixed with cement to pre cast and backfilling the voids surrounding the metal conductor in earth pit of 150 mm dia x 6000 mm depth, resulting in increase of effective surface area of the earth electrode to lower the desired earth resistance value (i.e. less than 1.0 ohms) , permanently with no further maintenance or periodic watering or recharge during it’s life of over 10 years in all type of soil including dry or rocky soils. Earth enhancing material should not leach into the adjacent soil or underground water channels and it’s pH value should be in neutral range complete all as specified and as directed. Note:- (i) Excavation and earth work , strips and pit cover shall be measured and paid seperately. (ii) Payment shall only be made after rendering gaurantee certificate against maintaining the desired result of less than 01 Ohm for 10 years from the date of completion. (iii) Testing of earthing shall be carried out in presence of Engr -in- charge and results shall be submitted to AGE(I) duly signed by all concern.

Excavation in trenches not exceeding 1.5 mtr wide and exceeding 1.5 m and not exc 3.0 m depth for earthing pit etc and getting out in hard/ dense soil compete all as specified and as directed.

Excavation in trenches not exceeding 1.5 mtr wide and exceeding 3 m and not exc 4.5 m depth for earthing pit etc and getting out in hard/ dense soil compete all as specified and as directed.

Excavation in trenches not exceeding 1.5 mtr wide and exceeding 4.5 m and not exc 6.00 m depth for earthing pit etc and getting out in hard/ dense soil compete all as specified and as directed.

Returning , filling in , including spreading levelling watering and well ramming in layers not exceeding 25 cms thick complete as in excavated soft/loose soil all as specified directed. Note: Good quality paddy field soil for RFR shall be measured and paid separately

Removing surplus soil to a distance not exceeding 50 mtr and depositing where directed including spreading levelling at a level not exc 1.5 mtr above the starting point as directed.

Supply only Good quality paddy field soil (soil obtained from outside of defence land) for filling in earthing pits, complete all as specified and as directed.

Supply and fix FRP earth pit cover of 400mm dia (top) and 480mm (bottom) with cover of colour (Green/Red/Yellow) complete all as directed.

Supply and fix 25x5 mm copper coated / bonded MS strip (minimum thickness of copper coating shall not less than 100 micron) fixed with saddles and stainless steel screws/nut etc as in roof conductor and down conductor above the ground level, complete all as directed.

Supply and fix 32x 6 mm GI strip fixed with saddles and stainless steel screws/nut etc as in roof conductor and down conductor above the ground level, complete all as directed.

Supply and fix Stainless steel screw/nut and bolts (machine made) with hexagonal or square heads at one end and screwed the other each screwed end to be fitted with washers and one hexagonal or square nut of dia 5 mm to 10 mm, n exc 25mm long complete all as directed.

Material and labour for test point terminal block made of gun metal or phosphorus bronze size 75x75x25mm drilled and screwed including 3 nos 8mm dia 25mm long hex head screw complete all as directed.

Material and labour for testing earth resistivity of work site and submitt complete report and design of earthing to achive desired value i.e less than 01 Ohm , complete all as directed.

Bhuiya Construction