REJUVENATION OF EARTHING PITS FOR L2 SWITCHES AND LIGHTING CONDUCTION PROVIDED AT HQ MC BLDG AT AF STN NAGPUR

Material and Labour for maint free safe earthing system burnished copper earthing electrolyte grade 78MM dia made of high tensile low carbon steel closed with 78MM electrolyte plate with set of four separate electrode to be used as grid earthing each pit complete with 01 Number UL 467 approved/CPRI tested copper bonded (copper cladded earth rod with 250 microns of copper cladding) earth rod with 78MM dia 3000mm long electrode Part( a) buried in ground to bore holes 150 mm dia vertically to a depth not less than 3500 MM deep below ground level or L shape in case of Rocky condition (2 ft deep and 8 ft horizontol) with top edge of earth electrode at a depth not less than 500mm below normal ground level,Part (b) provision of copper bus bar of size 200mm x 25mmx6mm for inter connection with copper earth lead strip 25mm x 3mm Purity test by Gun Method is not Less than cu 99.54,Iron 0.073,Zinc 0.387 and further connected to test point terminal block alongwith the protection pipe of size 40mm bore med grade and epoxy type insulator all as directed. Part (c) each earth pit shall include minimum 50kg (two bags of 25kg each) NABL lab Certified Marconite back fill compound Powder Having Elect Resistivity 2.590 Ohm,Vol.Free Swell Index(%) 120 & Swelling Vol.(Ml)-18.00,Ph ratio 9.10,Moisture Content (%)2.32 Water Holding Capacity (%)-320.50,Thermal Stability -(-10 to 60Deg.s)-Unity Methelyne blue Absortation (meq/100gm)-2.70,Bulk density (kg.metere cube)-69.17 mention parameters are as follows. and 6 kg (two container of 3kg Each) NABL Lab Certified conductive gel compound for filling bore holes with replacement of rocky soil with loamy garden soil mixed in 1:3 ratio (one part of back fill compound and three part of loamy garden soil), so as to achieve earth resistance below 1 Ohm including exacavation of polypit chamber with polyplastic pit cover heavy grade of size not less than 300mmx300mmx300mm and painted with weather proof red paint and identification marking (cost of poly pit chamber with polyplastic pit cover shall be deemed to be included in the rate quoted) complete all as specified and as directed by Engineer-in-charge. Make : S N Engineering , Dhruva Technology Pvt Ltd, Pragati, Ashgel Electrode, Becqueral Industries Pvt. Ltd, Earthing Raj Industries, Veraizen Earthing Pvt Ltd, Maratha Fast earth electrode, Trimurti Earthing, Eterntiy Energia Solutions or equivalent.

Note : (a) Contractor will provide test sheet duly signed by the Engr-in-charge on completion of earthing. (b) Copper strip beyond test point shall be measured and paid separately. (b) Contractor shall give guarantee of minimum 24 Months for the earting carried out by him (c) The rate quoted is inclusive of test point made of phosphorous bronze of size 75x75x25mm, drilled and screwed including 3 Nos 8mm dia 25mm long brass nuts and bolts complete all as directed. (d) Any other fittings /fixtures if technically required for archieving desired results (if not included above) shall be provided by contractor without any extra cost to the Govt. (e) On testing after completion if the desired resistenance i.e below 1 Ohm is not obtained the contractor shall redo the earthing without any extra cost of department. (f) Protection pipe upto equipment (if required) shall be deemed included in the unit rate for earthing. (g) Copper strip upto 7.5 RM shall be deemed included in the unit rate for earthing all as specified and as directed. (h) Earth pit to be inspected by the contractor or his rep on monthly basis in presence of one rep of AFNET power plant without any extra cost of department.. (j) Before excution of work Soil resistivity test, Fall of potential (3 Point) method, Thermal resistivity soil moisture test should be mandatary to carried out through Govt institute (Polytechnic) (NABL approved) and report to be submitted to Engr in charge (if the desire report not obtained from the soil the same replaced accordingly for better result of earthing. (k) Each Electrode Measured by Gauge measure M1 Type Micron is not less than 250 Micron.

Supply and Fix Earth continuity conductor or main earthing lead fixed to wall on batten or recess or chases or buried in ground or drawn in conduit/pipe or fixed to poles for loop earthing as required 25 x 3mm copper strip alongwith Purity test by Gun Method is not Less than cu 99.54,Iron 0.073,Zinc 0.387 and further connected to test point terminal alongwith earthing strip epoxy type insulator and must be supported at every 2.00 mtrs in intervals complete all as specified and directed .

Note : The amount against Schedule of Credit on Page No. 22 shall be deducted from the total amount quoted against Sch 'A' while deriving Acceptance