WORK OF CHEMICAL EARTHING SYSTEM AT 132 KV SUBSTATION PURNACHHAPAR UNDER ETD DEORIA

Supply installation commissioning and testing of complete set of Chemical Earthing System T/Fs at , 132KV S/S Purnachhapar under ETD-Deoria including excavation, making of earth pit, fixing of electrode with back fill earthing compound, fixing of earth cover, any other civil work as per the site engineer and as per drawing attached.

A) Construction of unit earth pit: a. A hole of 100mm to 125mm dia shall be augured /dug to a depth of about 3.0 meters. b. The carth 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 lhat min. 150 mm of the electrode shall be inserted in the natural soil. d. Earth enhancement material (minimum approx, 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 of 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 copper strip of 200mm x 25mm 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 IEEE 837 by NABL/LAC 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.

B) Const. of Inspection Chamber:- a, Inspection chamber should be as per IEC 62561-5 or latest. b. The dimension of the chamber will be of 300 x 300x300mm (inside dimension) of PVC with 50 mm thick and fine finish. c. The marking space should be present an PVC cover, d. The date of testing and earth resistance value shall be written on the cover with black base with yellow paint. C) Details of material to be used in above work and shall be provided by the contractor: 1. Details of Electrode: (i) 3 Mtr Long 17.2 mm dia, 250 microns molecularly bonded copper over steel rod with pre welded 04 Nos of hole termination along with SS Boll-nut, washer for fixing of interconnection and earth rod connection- 10 Set. 2.Earth Pit Chamber; (i) HDPE PVC Earth chamber with PVC cover having capacity of 5 Ton point Load of size 50cm x 50cm and earth bar-01 No along with double hole and lugs and cements bags 3. Grounding compound/Backfill Compound (ii)Curec. (in 3kg bag): 02 Bags Note: - All labour, T&P and Materials will be arranged by Firm/Contractor at his own cost