Redundancy technique is used to improve performance and achieving to increase the lifetime of a system. Nowadays, the redundancy method is applied in many industries. One of the common methods of redundancy is its utilization in the switching systems. In switching systems, one or more components are considered active mode and the others in the standby state to be used by switch if necessary. In order to be fully utilized all the components in the redundant device, the switch unit must perform its function, such as switching, perfectly. Successful Coverage by switch unit is expressed with a Probability. In this paper, a new approach to the likelihood of switch success is proposed, and showing that as increases switching in the system, the efficiency and performance of the switch gradually decreases. The analysis of this method was based on the stress-strength method. Finally, a few numerical examples for the validation of results were applied.