Following the incident of the 3rd of August 2002 where Yibal experienced a severe power dip at 4:14am, the failure of the VCB was one of the contributing factors and K5304 10MW electrical driven compressor at Yibal C was out of service for 136 hours, which is equivalent to 5.66 days with substantial oil deferment. The circuit breaker is question is OX36 Outdoor Vacuum circuit breaker and reinstated after faulty vacuum chamber was replaced (For further details contact ONO/12Y).