REPAIR/REPLACEMENT OF EXISTING CONVENTIONAL EARTHING PITS

Amount

Taking down carefully existing damaged/unserviceable Copper/GI strip and GI wire as in earth continuity conductor or main earthing leadfixed to wall on batten or recess or chases or buried in ground or drawn in conduit/pipe or fixed to poles or any other situation of any size and type, complete all as directed.

Taking down carefully existing unserviceable test point terminal block of any size and type complete all as specified and as directed.

Excavating in trenches, n exc 1.5 m wide and n exc 1.5 m in depth; for foundation, etc. or for shafts, wells, cesspits, manholes, pier holes, etc. n exc 10 sq m on plan and n exc 1.5 m in depth and getting out in soft/loose soil ,complete all as specified and directed.

Returning filling in soft/loose soil, including, spreading levelling watering and well ramming in layers not exc. 25 cm complete all as specified and directed.

Removing excavated soils to a distance not exceeding 50 Metres and depositing where directed at a level n. exc. 1.5 M above the starting point complete all asspecified and directed.

Materials and Labour for provision of concrete earthing pit as shown on electrical plate No 3 of SSR Part –I (2009), in PCC (1:3:6) Type C1, pre-cast RCC (1:2:4) type B1 cover slab 54 cm x 54 cm x 5 cm reinforced with 8 mm dia. TMT bars @ 150 mm centre to centre both ways, with one handle for lifting made out of 8 mm dia. MS bar, including demolition of existing damaged earthing pit and including necessary earthwork in any type of soil, complete all as specified and directed.

Supply Only Sodium Chloride (common salt) for artifical chemical treatment of soil for reduction of earth electrode resistance, complete all as specified. Notes:- (i) Material shall be supplied in standard packaging as per manufacturer's standards (ii) Material shall be delivered in the store yard of AGE E/M GE (AF) Tezpur and receipt voucher obtained.

Supply Only charcoal for artifical chemical treatment of soil for reduction of earth electrode resistance, complete all as specified. Notes:- (i) Material shall be supplied in standard packaging as per manufacturer's standards (ii) Material shall be delivered in the store yard of AGE E/M GE (AF) Tezpur and receipt voucher obtained.

Materials and Labour for, test point terminal block madeof gun metal or phosphorus bronze size 75x75x25mm drilled and screwed including 3 nos. 8mm dia 25mm long hex. head screw,complete all as specified and directed.

Materials and Labour for, copper strip 20 x 3.15mm with saddles and fixing screws etc.for roof conductors and down conductors above ground,complete all as specified and directed.

Materials and Labour for,copper strip 32 x 6mm buried in ground, complete all as specified and directed. Note:- Earthwork will be measured and paid seperately.

Materials and Labour for,galvanised iron strip 32 x 6mm buried in ground, complete all as specified and directed. Note:- Earthwork will be measured and paid seperately.

Materials and Labour for,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 or any other indicated situation for loop earthing etc. as required 4 mm dia galvanised iron or steel wire, complete all as specified and directed.

Supply and Fix in repairs, brass screw bolts (machine made),diameter of shank 8 mm, length of bolt 25 mm long,with hexagonal heads at one end and screwed the other,each screwed end to be fitted with washers and one hexagonal or square nut,complete all as specified and directed.

Materials and Labour for, brazing of mechanical joints in earth continuity conductor or main earthing lead from one end to other end, complete all as specified and directed.

Alignment of existing Copper/GI strips of any size as in roof conductors and down conductors above ground by replacement of damaged saddles with new saddles and fixing screws etc. including making good disturbed surfaces of floors/walls/ceiling etc complete all as specified directed.

Materials and Labour for earthing complete with galvanised steel earth plate electrode 600 mm x 600 mm x 6 mm thick buried directly in ground vertically to a depth not less than 2.25 meter deep below ground level with top edge earth plate at a depth not less than 1.5M below normal ground level connected to galvanised steel earth lead wire 4 mm dia. by means of bolts, nuts check nuts and washers of galvanised steel and connected to main switch board or main control board as directed and including provision of concrete pit in PCC (1:3:6) type C1, pre-cast RCC (1:2:4) type B1 cover slab 54 cm x 54 cm x 5 cm reinforced with 8 mm dia. TMT bars @ 150 mm centre to centre both ways, with one handle for lifting made out of 8 mm dia. MS bar, provision of funnel, wire mesh, 20 mm bore galvanized steel tubing (Medium grade) for watering, charcoal or coke and salt in alternate layers, 15 mm bore galvanized steel tubing medium grade for protection of earth lead connection, necessary excavation and earth work in any type of soil complete all as specified and indicated on electrical plate No 3 of SSR Part –I (2009) including testing on completion.

Materials and Labour for earthing complete with galvanised steel earth plate electrode 600 mm x 600 mm x 6 mm thick buried directly in ground vertically to a depth not less than 2.25 meter deep below ground level with top edge earth plate at a depth not less than 1.5M below normal ground level connected to galvanised steel earth lead strip 32 mm x 6 mm by means of bolts, nuts check nuts and washers of galvanised steel and connected to main switch board or main control board as directed and including provision of concrete pit in PCC (1:3:6) type C1, pre-cast RCC (1:2:4) type B1 cover slab 54 cm x 54 cm x 5 cm reinforced with 8 mm dia. TMT bars @ 150 mm centre to centre both ways, with one handle for lifting made out of 8 mm dia. MS bar, provision of funnel, wire mesh, 20 mm bore galvanized steel tubing (Medium grade) for watering, charcoal or coke and salt in alternate layers, 40 mm bore galvanized steel tubing medium grade for protection of earth lead connection, necessary excavation and earth work in any type of soil complete all as specified and indicated on electrical plate No 3 of SSR Part –I (2009) including testing on completion.

Materials and Labour for maintenance free chemical earthing system using single spike 17.2mm dia, 3000mm long high tensile low carbon steel circular rod, molecularly bonded with copper on outer surface (minimum copper bonding thickness of 250 microns) meeting the requirements of Under Writers laboratories (UL) 467-2007 or latest with 250mm long copper strips of size 50X3 mm, exothermally welded on top of electrode complete including augering (boring) 100-125mm dia hole as required for electrode in any type of soil and back filling with Earth Enhancing Chemical back filled compound as per IEEE 80 2000 Clause 14.5(c), conforming to IEC 62561-7, min quantity of compound used 40Kg), i.e. total qty 40 Kg per electrode, conforming to IEEE/BS standrads including pit cover light weight made out of high quality polymer with lid made of HDG steel, including nessary testings and commissioning, complete all as specified and as directed. Notes:- (i) The work of earthing shall be carried out by authorised trained rep of OEM. (ii) The acceptable earth resistance at earth busbar/ test point shall be as per users requirement as desired by Engr-in-Charge but it should be below 01 Ohm. At certain locations, it may not be possible to achieve desired earth resistance with one electrode / pit due to higher soil resistivity,in such cases, provision of loop earthing consisting of more than one earth electrode pits shall be done. The number of pits required shall be decided based on the resistivity of soil and resistance achieved for the earth pits already installed. The distance between two successive earth electrodes shall not be less than 3 metres. (iii) The procedure mentioned here-in-before for one earth pit shall be repeated for other earth pits. (iv) Additional earth electrode pits and loop conductor shall be measured and paid seperately . (v) The quoted rate shall also be included the following elements: (a) Complete earthwork including drilling holes for electrode.(b) Earhing electrode-01(One) No Only (c) Backfilling carbon based ground enhancing compound (GEC). (d) Pit cover light weight made out of high quality polymer with lid made of HDG steel. (e) Soil suitable for agricultural purpose required for each pit (f) Copper strip as earthing lead of size 50mmx3mm, 250 mm long only, beyond 250mm, other size will be measured and paid for separately under respective item(s) in this BOQ. (g) All Labour and T&P required including testing of earth network. (vi) Testing for earth resistance shall be carried out in presence of GE and Engr-in-Charge. (vii) Taking out existing unserviceable earthing system complete. (viii) Original purchase vouchers for copper rod and back fill compound and manufacturer test certificate of entire quantity shall be produced by the contractor before commencement of work. (ix) The Earthing shall be carried out with Soil suitable for Agricultural purpose.

M/S A K MITRA

M/S Mandeep Singh