Provn of Earthing pits for AFNET and CPSS infrastructures at 5 AFSB under GE (AF) Borjhar

Amount

M&L for excavating in bore holes of 300 mm (minimum) dia to a depth of 3450 mm (minimum) by augur or any other process trenches manually not exceeding 0.5 cum in each bore complete incl removing surplus excavating material, returning filling for chemical earthing in soft / loose soil all as specified and directed.

Supply, install, testing & commissioning of maintenance free chemical earthing by pure Copper Electrode of 17.2mm dia and 3000mm long for earthing with excellent electrical conductivity and corrosion resistance, minimum 50 kg ground enhancing compound/ material used around the electrode inside the earth pit to define the working environment of the earthing system complete all as specified and directed. Make : Electrode - 99.9% pure copper rod with test certificate for purity from any Government lab, Ground Enhancing Compound-ABB/ OBO The process for the earthing are appended below:-

i) Soil resistivity of that area shall be measured. ii) If soil resistivity is more, then multiple earthing shall be carried out in grid pattern i.e if two earthing is reqd then the pattern is" ── " and if three earthing is reqd the the pattern is "∆", but a minimum distance of 2 meters between two earth pit should be maintained. However, there should not be more than three earthing pit in a grid. iii) Make a bore of 300 mm (minimum) dia to a depth of 3450 mm (minimum) by augur or any other process. iv) The soil dug out from the earth pit shall be checked to remove lumps and stones from it, before back filling. v) Moisture retaining ground enhancing materials of minimum 50 kg having resistivity equal to or less than 0.3 Ωm shall be poured in the bore. vi) A layer of 150mm of the above ground enhancing materials shall be prepared at the bottom. vii) Plastic sleeves from electrode shall be removed before it is lowered in the pit. viii) Small quantity of ground enhancing material shall be filled at a time and some water in the pit. Further quantity shall be added after the earlier quantity has been sufficiently poked with suitable rod to remove trapped air bubbles from it. ix) If grid earthing is reqd. necessary interconnection shall be carried out by 20X3mm copper strip which shall be buried below 300mm from G.L with additional quantity of ground enhancing material & cost of the same is deemed to be included in this rate x) The above arrangements shall be provided with Heavy duty earth champer of 5000kg load bearing capacity to ensure the safety of earthing system OBO Type No.UFE (5450 03 0) Make :OBO Bettermann/ABB . xi) A coat of conductive petroleum jelly shall be applied on the terminal of the electrode & copper alloy clamp for protection against corrosion. xii) A certificate from the Government lab for purity of the electrode and resistivity of ground enhancing compound /material shall be furnished prior approval of sample.

Note : i) If more than one earthing is reqd due to high soil resistivity at site the payment shall be carried out by measuring extra quantity ii) The copper strip and protection pipe beyond 7.5 m length shall be measured and paid separately .The strip for grid earthing shall be measured & paid separately iii) The cost for excavation, returning, filling in & removing of soil shall be measured & paid in the item as mentioned below, however form work if reqd is deemed to be included in this rate iv) The desired value of earth resistance should be less than 1 Ω & after testing in presence of the rep of the Engr-in-Charge, if the earth resistance value is not obtained, the earthing will be redone at no extra cost, otherwise it will not be measured and paid to the contractor. v) The quantity of ground enhancing material as mentioned above is tentative, due to site condition if additional quantity of ground enhancing materials are reqd, the contractor is bound to provide additional quantity without demanding extra payment for the same from the department. However, the maximum quantity of ground enhancing materials used for chemical earthing pit and grid connections are 75 kg. vi) During earth work if surface water found at site, the cost for dewatering through pumpset is deemed to be included in this rate.

M & L for earth continuity conductor or main earthing lead fixed to wall / roof by dmc insulator (as reqd basis) on any other indicated location for loop earthing etc with 20x3mm copper strip all as specified & directed. (Copper strips should be fixed on cleat insulator of 60 cm apart if reqd)

S&F galvanized steel tubes of 40 mm bore light grade including all fittings like bend & socket and fixed on walls / ceilings / floors through MS clamp for earth strip protection complete all as specified and directed.

M & L for test point terminal block made of gun metal for phosphorous bronze size 75 X 75 X 25 mm, drilled and screwed including 3 Nos. 8 mm dia 25 mm long hex head screw within halogen free weather proof IP-66 enclosure with one/ two nos mounting bracket all as specified and directed. Enclosure Make : Hensel/ OBO (The test point should be 1.0 mtr above ground level)

S&F High galvanized mast light 15 Mtr suitable for 6 to 9 lantern symmetrically fitted along with their control gear and having two point suspension system with stainless steel wire rope of 6 mm dia 97/19 guage and double drum winch with luminaire mounting arm, pully assembly, aviation obstruction light, lightning arrester spike including RCC foundation as per height complete all as specified and as directed.

Supply and fixing LED flood light 170 watt 230 V AC outdoor type with thermal management in multiple optics and equipped with IP 66 protection, with impact and corrosion resistant complete with driver and lamp complete all as specified and directed.

Supply and fixing 1100 volts heavy duty round sheathed multistranded three core bright annealed copper conductor cable of size 1.5 Sqmm for electrical connection to the High mast from main control switch to light fittings complete all as specified and directed by Engr-in-Charge

M&L, connecting of 1100 volt grade heavy duty XLPE cable with PVC insulated aluminium conductor served with inner sheathing of PVC tape armoured with galvanized steel strip or wire and overall PVC sheathed of size 50 Sqmm nominal cross section 3.5 core laid in trenches, fixed to pole or passing through pipes including all necessary clamps, nuts, bolts washers testing and commissioning complete all as specified including taking out existing unserviceable cable from trenches, floor, ducts, poles or roads complete all as specified and directed (Earth work shall be measured and paid separately).

Excavation in trenches not exceeding 1.5 mtr wide and not exceeding 1.5 mtr depth and getting out in soft/loose soil for lying of cable etc complete all as specified and directed by Engr in charge.

Material and labour for sand cushioning for under ground cable with locally available sand for protection of cable including spreading and consolidations, complete all as specified and directed.

Supply and laying in trenches dry well burnt locally available sub class “B” bricks over sand cushioning for protection of cable complete all as per specified and directed.

M&L for returning, filling in, including spreading, watering and well ramming in layers not exc 25cm in soft/loose soil.

M&L for removing surplus soil to a distance not exc 50m and depositing where directed at a level not exc. 1.5m above the starting point.

M & L of GI pipe 40mm dia bore light grade with all fittings for cable protection, and fixed complete to wall, panel, pole or laid in trenches and road crossing complete.

Supplying, installation,commissioning and testing of LT panel 3 Phase 4 wire system outdoor type factory made, supported with MS angle iron frame of size 50x50x6mm, dust and vermic proof cubical type interlocking arrangement (IP-65 protection) fabricated with 3.15mm CRCA sheet with Anticorrission & finally polyester powder coated of finite greenfully compartment with providing with suitable size of coated aluminium busbar strip complete all as specified for the following:- a) Incoming i) MCCB 40 Amps 4 Pole, 415 Volts, 25 KA-01 No b) Outgoing i) MCB 32 Amps 4 Pole, 415 Volts 10 KA -02 Nos ii) MCB DP 32 Amps , 230 Volts 10 KA C Curve - 02 Nos iii) Indicating Lamp (RYB) 01 set of 3 iv) Insulated aluminium bus bar rating 150 Amps 3 Phase neutral -01 set v) Chamber for incoming and outgoing cable. vi) 2 x Spare space for Double pole MCB.

M & L for earthing complete with galvanised steel earth plate electrode 600 x 600x 6mm burried directly in ground (earth pit not less than 2.25 mtr deep below ground level) with top edged of the plate not less than 1.5 mtr below normal ground level, connected to galavanised iron earth lead by means of bolt, nut, check nut and washer of galavanised iron steel wire 4mm dia as earthing lead as shown in Electrical Plate No 4 of SSR Part I connected to earthing test point all as specified or indicated including testing on completion including necessary excavation and earth work in soft/ loose soil, earth pit in PCC 1:3:6 type C1 using 20mm stone aggreate, funnel, 20mm dia GI med grade water pipe, 15mm dia GI light grade earth lead protection pipe, CI frame and cover, wire, copper lugs, wire mesh, charcoal or coke and common salt in alternative layer all around the earth electrode compacted thickness 15 cm including excavation and earth work pit cover including disposal of surplus soil to a distance not excessding 50m, complete testing on completion all complete as shown in electrical plate no-4 of SSR part No1 complete all as specified and directed.

Goswami Traders (BID ID -3219507)