With the growth of the electricity demand, utilities have been upgrading their systems continuously for higher power transfer capability and consequently, for higher fault current handling capability. There are growing instances in utility distribution and transmission systems wherein the fault current levels are exceeding the interrupting capability of existing substation circuit breakers. This increase in fault current level either requires the replacement of a large number of substation breakers or the development of some means to limit the fault current. Also, many mechanical circuit breakers are operating beyond the capacity originally intended in applications such as capacitor switching. This continual use of mechanical breakers requires intensive maintenance to be performed or periodic replacement of the whole breaker. Also the process of replacing circuit breakers of adequately high fault current interruption capability can become an expensive exercise. Environmental concerns with the use of both Sulfur Hexafluoride (SF6) gas and oil within mechanical breakers may pose long term problems for many utilities.