tender for major overhauling of 420kv sf-6 c.b. (cgl make) installed in400 kv baysat400 kv sub-station unnao - major overhauling of 420 kvsf-6 circuit breaker (cgl make) installed at 400 kv unnao-mohanlalganj bay, 400 kv unnao-agra bay, 315 mva ict-iii, 400 kv tbc bay and 400 kv bus coupler bay at 400 kv sub-station unnao by making an inert chamber (working place) of wooden /steel frame then covering whole area to prevent job from external atmosphere /dust/pollution etc. extraction of sf6 from all three poles of 400 kv sf6 circuit breakers in empty sf6 gas cylinder. safe dismantling of all three poles of 400 kv sf-6 c.b. with the help of hydra/ crane of suitable capacity and carriage up to the working place, then major overhauling of complete 400 kv sf-6 c.b. including pir, interrupter unit and complete operating mechanism by opening of all parts, cleaning of all parts and chamber then replacement of defective parts, o-rings etc. if required then compete assembling of circuit breaker unit. safely carrying back of the overhauled breaker unit from work place to installation place then complete erection of all three poles of 400 kv cb on structure and connecting the clamp and connector with 4” ips pipe bus. creating vacuum in all three poles and after that filling of sf-6 gas up to the required pressure then checking of leakage of gas with the help of detector. checking of operation withcb analyser and complete testing and commissioning of the circuit breaker to secure for proper operation. all the consumable materials, t&p, crane, gas handling plant, cb analyzer, skilled and unskilled technicians, experienced engineers capable to work on cgl make circuit breaker to be arranged by contractor on his own cost. (all required o-rings, spare parts of cb will be provided by upptcl free of cost).