PROVISION OF NEW EARTHING PITS ALONG WITH EARTH RESISTANCE TOMOGRAPHY AT VARIOUS LOACATIONS AT AF STN DINJAN PHASE II UNDER GE(AF) MOHANBARI

Amount

PHASE - I M&L for study of earth/soil resistivity (tomographic survey of soil) by Conducting earth resistivity test using earth tester to find out the resistivity of the plot and to obtain polar resistivity curve and average resistivity in eight direction at AF Stn Dinjan and submitting the report with recommendation and complete detailed specification of earthing to be considered for obtaining earth resistance value less than 1 ohm, complete all as specified and directed. Note :- (i) The unit rate also include for necessary excavation in any type of soil (ii) Report shall be submitted in duplicate set. (iii) Study at one location shall be measured and paid at one job. (iv) Contactor shall submit guarantee @ 5% of quoted rate against this item to ensure earthing results as per design. The same shall be released after successfully completion of Phase-II.)

PHASE II M&L for installation and testing of maintenance free earthing (as designed and approved under Phase-I) complete with earth electrode as per IS 3043 or latest tested for 254 micron copper bonded low carbon steel core of 3 meter long, 50 mm dia with 25x3 mm inner copper strip buried directly in ground and tapered at the bottom 175- 200 mm dia digging or auguring of earth to the required depth as approved tomographic survey report (received under Phase I above) and filled up in bottom with slurry 10 Kg plain bentonite for moisture and then with earthing chemical as per design under Phase-I as per IS/ IEC-62561-7 of Balanced Ph and less than 0.2 Ohm Resistivity carbon based earth enhancing compound in slurry form and quantity as per design. An arrangement for connection of copper strip (25x3mm) to rod connected by means of Universal Copper Ground Rod Clamp of size 135x35x3mm to the electrode, copper earth strip 25x3 mm connected by means of clamp, provision of HDPE pit cover with minimum 5KN load capacity chamber with cover including necessary excavation in any type of soil, returning filling in, removal of surplus soil complete all as specified and directed. Contd....

Note:- (i) Phase-I completion is mandatory prior to start of work at a particular location. (ii) Earthing system shall be designed so as to achieve test result less than 1 Ohm depending upon the soil conditions for the minimum 2 Years under warranty. (iii) Copper strip to be extended upto the equipment and power room. It should be routed on the side wall of the underground duct fixed with ceramic/ porcelain/ PVC spacers and hot sleeves. (iv) Readymade HDPE pit chamber with cover having minimum load capacity 5 KN with connected items. (v) Copper strip should be 25x3 mm and length upto 7.5 Mtr is deemed to be included in the item qouted rate. (vi) The number of earthing electrode in each earthing pit shall be as per design carried out in Phase-I. Any extra cost for universal number of pits as per design shall be deemed to be included in item quoted rate. (vii) The Phase-II work shall be commenced after completion of Phase-I work. Make: As approved by GE on the basis of report received under Phase-I.

M&L for 25X3 mm copper strip for earthing connection to building, complete all as specified and directed.

Supply and fixing GI protection pipe of 40 mm dia light grade for cable protection including all fittings laid in trenches or fixed on pole/ walls/ laid in floor with mild steel clamps, bolts, nuts and washers complete all as specified and directed.

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