According to the definition of the Capital Goods, under CENVAT credit Rules, 2004 as amended time to time, CENVAT Credit on Spares, Components can be availed even if these spares/components do not fall under the same tariff heading as of the capital goods.
As enumerated above by Mr. James, CENVAT credit on such spare parts/components, can be availed to the extent of 50% in the first financial year and the remaining 50% will be availed in the next financial year( but after installation of spare parts/components.