bids are invited for repair, maintenance, and installation of plant/ systems/equipments (version 2) - substation; switchyard; service provider chemical earthing to be done on 220/132 kv and 220/33kv, 132/33 kv transformers installed at 220 kv substation nanauta under etd-ii, saharanpur.supply, installation, commissioning and testing of complete set of chemical earthing system on 220/132 kv and 220/33kv, 132/33 t/fs and 220/132/33 kv switch yard x,y point earthmat installed at 220 kv substation nanauta under etd-ii, saharanpur including excavation, making of earth pit cover, any other civil work as per the site engineer and as per drawing attached. scope of work: a) construction of unit earth pit:- a. a hole of 100 mm to 125 mm dia shall be augured/dug to a depth of about 3.0 meters. b. the earth electrode shall be placed into this hole. c. it will be penetrated into the soil by gently driving on the top of the rod.here natural soil is assumed to be available at the bottom of the electrode so that min. 150 mm of the electrode shall be inserted in the natural soil. d. earth enhancement material (minimum app. 30-35 kg) shall be filled into the augured/dug hole and allowed to set. after the material gets set, the diameter of the composite structure (earth electrode + earth enhancement material) shall be minimum 100 mm dia covering entire length of the hole. e. remaining portion of the hole shall be covered by backfill soil, which is taken out during auguring /digging. f. a gi strip of 50mm x 6mm shall be exothermically welded to main earth electrode for taking the connection to the main equi-potential earth busbar in the equipment room and to other earth pits, if any. g. exothermic weld material shall be tested as per provisions of ieee837 by nabl/ilac member labs. h. the main earth pit shall be located as near to the main equi-potential earth busbar in the equipment room as possible total quantity :