FI residual current circuit breaker, 2-pole, Type A, In: 125 A, 300 mA, Un AC: 230 V. The residual current circuit breaker is the protective device for touch protection against fault currents. Siemens' patented residual current protective devices are an essential component of the SENTRON protective devices for electrical installations, as they prevent life-threatening electrical accidents by safely disconnecting dangerous fault currents to ground. Electrically ignited fires can be prevented at their inception. Whether through direct contact with live parts or indirect contact with operating equipment, protection is primarily achieved through rapid disconnection. The residual current circuit breakers are characterized by: 1. Comprehensive protection for individuals and assets against electric shock 2. Whether sinusoidal alternating fault currents or smooth direct fault currents - Siemens offers the right type and special versions for all requirements 3. Be protected in accordance with standards.