The Disconnecting Circuit Breaker (DCB) with Fiber Optic Current Sensor (FOCS) from ABB is suitable for use with IEC 61850-9-2LE process bus communication. The Fiber Optic Current Sensor changes the conventional current transformer for current measurement. This device has three functions - measurement, interruption, isolation. The FOCs, once is installed with the DCB, offers various benefits that includes an enhanced short circuit performance, quick installation, a simplified design and engineering substations, environmental friendly, as well as intelligent protection and control using is smart process bus interface. The DCB offers the functions of a circuit breaker and a disconnector integrated in a single unit. It is commonly used in Line, transformer, reactor and capacitor switching as well as switching for harmonic filters.