supply of 250kva outdoor transformer:- 250 kva, 6kv / 415v, 3-phase, 50hz, outdoor type, plinth mounted, oil immersed, non-sealed type, supply of 250kva outdoor transformer:- 250 kva, 6kv / 415v, 3-phase, 50hz, outdoor type, plinth mounted, oil immersed, non-sealed type ( transformer tank body and cover are bolted ) distribution transformer, primary winding in delta and secondary winding in star ( vector symbol- dyn11 ) , onan cooled transformer, energy efficiency level- 3 & above. transformer shall be conforming to is 1180 ( part 1 ) : 2014 with amendment nos. 1, 2, 3 & 4, and supplied with all standard fittings mentioned in clause 20.1 of is 1180 ( part 1 ) along with oil temperature indicator & winding temperature indicators, drain-cum sampling valve ( 3 / 4 nominal size thread, is:554 ) of steel with plug. terminal arrangement:- the transformers shall be fitted on high voltage and low voltage sides with bushings of appropriate voltage and current ratings. the high voltage bushings ( 3 nos. ) shall conform to is / iec 60137. the low voltage bushings ( 4 nos. ) shall conform to is 7421. suitable cable- end box is to be provided in ht & l.t. both side. tap changer: offload tap changer for variation of hv voltage from +5% to -10% in steps of 2.5%. following has to be submitted along with supply of material: ( i ) type test report as per is: 1180 ( part 1 ) of transformer having same rating, make ( & model if any ) and design from nabl accredited lab, ( ii ) routine test certificates as per is: 1180 ( part 1 ) , ( iii ) special test certificates as per clause 21.4 sl. no. ( a ) , ( c ) , ( d ) & ( e ) of is:1180 ( part 1 ) [ warranty period: 30 months after the date of delivery ]