REPAIR / MAINTENANCE OF EARTHING AT VARIOUS LOCATION AT HQ EAC (U) AF UNDER GE (I) AF SHILLONG

Excavation in trenches not exc. 1.5 m wide not exc. 1.5 m in depth; for laying of cables not exc. 10 Sqm on plan and getting out , trimming sides, forming bottom surface to required level complete in hard/dense soil all as specified and as directed.

Excavating in trenches, not exceeding 1.5 mtr wide and exceeding 1.5 mtr in depth but not exceeding 3.0 mtr depth ; for foundation, etc. or for shafts, wells, cesspits, manholes, pier holes, etc. not exceeding 10 sqm on plan and getting out soft/loose soil complete all as specified.

Returning, filling in, including spreading, levelling, watering and well ramming in layers n.exc. 25cm thick as in soils all as specified and as directed.

Removing of excavated soil to a distance not exc. 50m and depositing where directed at a level n.exc 1.5m above starting point all as specified and as directed.

Material and labour for earthing with copper earth plate electrode 60 cm X 60 cm X 3.15 mm thick burried directly in ground (earth pit not less than 2.25 mtr below ground level) with top edge of the plate not less than 1.5 mtr below ground level connected to 20 mm x 3 mm thick copper strip protected by 40 mm bore light grade galvanised iron pipe and other end connected to test point as directed including funnel with wire mesh and watering pipe 20 mm bore medium grade galvanised iron pipe with charcoal and common salt in alternaterlayers of 15 cm thickness all around the copper plate electrode with concrete pit in PCC 1:3:6 type C-1 with cast iron frame including cast iron cover10mm thick hinged to CI frame and 8mm MS rod for handle including painting with synthetic enamel paint of approved colour and put number marked with GI plate above 45 cm from ground level as per colour code in AF station, necessary excavation and earth wok in soft/loose soil and disposal of spoil to a distance n exc 50 m and necessary testing complete all as shown in electrical plate No 3 of SSR part-I including taking out old earthing all as specified. Note: (i) The cost of earth lead /strip and GI pipe for protection of earth lead/strip upto 7.5m is included in the quoted rate. (ii) The cost of excavation, earth work is included in the quoted rate. (iii) The ohmic value shall no be more than 03 ohm. (iv) If the resistivity of the soil not achieved the required ohmic value as per above. The Contractor shall arranged further grids to achieve necessary ohmic value. No extra payment shall be made for additional grids and for testing of soil for getting the ohmic value. (d) During payment of RAR/ Final Bill the contractor shall submit necessary report of ohmic value for each location duly signied by Contractor, JE and Engineer-In-Charge.

M & L for earthing complete with galvanized steel earth plate 60 cm X 60 cm X 6 mm thick buried vertically in ground to depth not less than 2.25 metres deep below ground level, with top edge of earth plate not less than 1.5 m below ground level, connected to galvanized iron strip 32x6mm earth lead by means of bolts, nuts, check nuts and washers of galvanized iron or steel besides welding at all joints as shown in drawing and including excavation and earth work, GI pipe light grade 40mm bore for protection of earth wire and connected to continous earth lead on pole/test point, supplying and laying charcoal dust common salt PCC 1:2:4 type B1, chamber and MS angle iron frame 40x40x3mm and RCC cover 40mm thick (1:2:4) type B1 using 20mm graded stone aggregate reinforced with 6mm dia round bars @ 75mm C/C both ways with MS handle 12mm dia, PGI/CI funnel and wire mesh, 20mm dia GI pipe medium grade for watering all as shown in electrical plate No 5 on srl page No 497 of SSR Part I (2009) drawing and connection to earth test point including testing and including dismantling and taking out old earthing complete all as specified and directed. Note : (i) The cost of earth lead /strip and GI pipe for protection of earth lead/strip upto 7.5m is included in the quoted rate. (ii) The cost of excavation, earth work is included in the quoted rate. (iii) The ohmic value shall no be more than 03 ohm. (iv) If the resistivity of the soil not achieved the required ohmic value as per above. The Contractor shall arranged further grids to achieve necessary ohmic value. No extra payment shall be made for additional grids and for testing of soil for getting the ohmic value. (d) During payment of RAR/ Final Bill the contractor shall submit necessary report of ohmic value for each location duly signied by Contractor, JE and Engineer-In-Charge.

Supply, installation of maintenance free Chemical Earthing system with 76.2 mm diameter x 3mtrs. long Earth electrode,hot dip galvanized 80-100 micron zinc. coated ,pipe filled with molecularly bonded crystalline conductive material in order to prevent the pipe from inner corrosion. The inner strip must be of size 25mm x3mm and the connecting outer terminal must be of size 50mm x6 mm. 6-8 inches dma bore must be made up to 10.5 feet depth. The pipe should be placed on the center of the Earth pit and the pit sorroundings must be filled with Electrolyte/Conductolyte compound at least 75 kg.The compound should be filled with necessary processing as advised by company representative. In case where soil resistivity is high additional loops may be made by adding more number of electrodes to achieve the required result and the same shall be paid including this item. The connections must well be made with hot dip galvanized 80-100 micron Earth Strip as per required sizes for various devices as specified.The Strip at ground level should be covered with heat shrink PVC Sleeve and the wiring must be insulated by providing DMC insulator and GI saddle.The joining of strips should have at least two nut bolts and the same should be welded properly so that no free space exhists on joints.Each joint should be oiled and painted to prevent corrosion. The Earth pits should be covered with Pit Cover of size1.5 ft dia x1.5 foot length and must be Mason worked with brick and cement to hold the pit cover firmly. Each connecting points for devices should possess Earth bar of size 300 x300 made of copper 6 terminal box type which should possess insulation.In case where proper clayaee soil is not available then a pit of dia 1.5 mtrs must be dug. Before Earthing installation of electrodes necessary processing must made for soil treatment as guided by company representatives. Note: (a) The ohmic value shall no be more than 01 ohm. (b) If the resistivity of the soil not achieved the required ohmic value as per above. The Contractor shall filled with fresh soil from outside with such restivity to achieve such ohmic value. No extra payment shall be made for pouring outside soil, testing of soil for getting restivity and necessay soil shall be paid and measured including this item. (c) Additional BFC required to achieve the ohmic value shall be measured and paid including this item. No extra cost shall be made to the contractor. (d) During payment of RAR/ Final Bill the contractor shall submit necessary report of ohmic value for each location duly signied by Contractor, JE, Engineer-In-Charge and by the user representative.

Supply only chemical i.e. ground enhancing compound (GEC) in bag of 25 Kg BARON Back Fill Compound (Conductolite) each complete all as specified and directed.

Taking out old unserviceable 20mm bore GI watering pipe of earthing and S & F 20mm bore Galvanised steel tubing medium grade as watering pipe of earthing etc conforming to IS-1239 complete all as directed.

Taking out old unserviceable copper earth strip and M & L for Earth continuity conductor of 20x3mm copper strip fixed to wall on batten or recess or chases or buried in ground or drawn in conduit/pipe or fixed to poles or any other indicated situation for loop earthing etc, complete all as directed.