Multi-components electrical equipment has multiple failure modes. In the context of condition-based maintenance, it is inefficient if executing maintenance for a particular failure mode. Based on analysis of economic independence, opportunistic maintenance is a special preventive maintenance which can coordinate different maintenance for multiple failure mode. Furthermore, steady availability of equipment was quantified with inspection frequency and opportunistic maintenance strategy. Finally, maximizing steady availability of equipment with inspection frequency constraints to construct model. Feasibility and validity of the model are investigated through case study.