CA NO. GE (I) (AF)/SHL/ OF 2021-22 PROVN OF CHEMICAL EARTHING PITS AT VARIOUS LOCATIONS AT HQ EAC (U) AF, UNDER GE (I) (AF) SHILLONG

Amount

Excavation in trenches in soft / loose soil, not exc 1.5 m wide and n. exc 1.5 m depth or n exc 10 Sqm on plan & getting out, for laying of cables, foundations of poles, struts, stays etc. and getting out including triming and forming bottom surface complete, all as directed.

Excavation in trenches in soft / loose soil, not exc 1.5 m wide and exc 1.5 m & n. exc 3.0m depth or n exc 10 Sqm on plan and exc 1.5 m & n. exc 3.0m depth & getting out, for laying of cables, foundations of poles, struts, stays etc. and getting out including triming and forming bottom surface complete, all as directed.

Returning, filling in, including spreading, levelling, watering and well ramming in layers not exceeding 25 cms thick in soft / loose soil back in trenches after cables have been laid and tested, poles, stays , struts have been erected and tested complete all as directed.

Removing excavated materials to a distance not exc 50m and depositing where directed at a level not exc 1.5 m above the starting point in soils complete all as directed.

M & L for constructing new earth pit chamber in PCC 1:2:4 type B-1 and RCC earth pit cover 50mm thick (1:2:4) type B1 using 20mm graded stone aggregate reinforced with 6mm dia round bars @ 75mm C/C both ways and edges of cover continuously protected with MS angle iron frame 40x40x3mm including provision of MS handle 12mm dia, complete all as specified and directed. Note : (i) Cost of formwork for earth pit chamber and cover & reinforcement of cover shall be deemed included in the quoted rate. (ii) Net volume of concrete shall only be measured and paid.

Supply, installation, testing and commissioning of maintenance free chemical earthing station using 76.00mm dia, 3000mm long high tensile low carbon steel circular pipe duly filled with CCM (crystalline conductive material), molecularly bonded with copper on outer surface (minimum copper bonding thickness 250 microns) meeting the requirements of under writers laboratories (UL) 467-2007 with 250mm long copper strips of size 50X3mm, exothermally welded on top of electrode complete including augering (boring) 250mm dia hole as required for electrode in any type of soil and back filling with carbon based ground enhancing compound (GEC) (with minimum qty 50 Kg per electrode) conforming to IEEE/BS standards complete with cover all as specifed and as directed. Notes:- (a) The work of earthing shall be carried out by authorised trained rep of OEM. (b) The acceptable earth resistance at earth busbar/test point shall not be more than 0.1 Ohm. (c) Loop conductors with copper strip 20mm X 3mm shall be measured and paid seperately. (d) The Earth result shall be achieved less than 0.1 Ohm. In the event of earth resistance found higher than earthing shall be re-done/rectified and no payment shall be allowed for earthing have earth resitance result more than 0.1 Ohm. (e) The cost of excavation, earth work i.e. augering described against this item is deemed to be included in the quoted rate and excavation, earth work other then augering shall be measured and paid separately against respective items of BOQ. Make: JEF Techno Solution Pvt/Tercel/McML/Macmet/ Erico/ Reslow JK earth electrode.

M & L for Earth continuity conductor of 20x3mm copper strip 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, complete all as directed.

Supply and fixing low density polythelene pipes (LDPE) 40mm dia for insulation of earth strip from building at entry points complete all as directed.

S & F solid copper lightening arrester of size 14mm dia, 1.2 metre long, with solid ball having four multi point spikes with heavy duty base plate complete all as specified and directed.

S & F Test point terminal block made of 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.

M/S BISWA CONSTRUCTION