PowerHub Static Transfer Switch STS manages the redundancy of the power supply system which composed of two independent powers to get a continuous and reliable power output. It can pre-select between the two inputs as default primary and backup source according to user’s requirement. In cases of breakdown of primary source, STS will immediately switch to the backup power supply automatically. The design of this STS ensures that there will be no dual input supplying at all times, with capability to prevent over-current or voltage from happening.