FI residual current circuit breaker, 4-pole, Type A, In: 80 A, 300 mA, Un AC: 400 V, SIGRES (for harsh environmental conditions). The residual current circuit breaker is the protective device for touch protection. Siemens' patented residual current devices are an essential component of the SENTRON protection systems for electrical installations, as they prevent life-threatening electrical accidents by safely disconnecting dangerous leakage currents to ground. Electrically ignited fires can be prevented even in their early stages. Whether through direct contact with live parts or indirect contact with operating equipment, protection is primarily achieved through rapid disconnection. The Siemens FI circuit breakers 5SV are particularly characterized by: 1. comprehensive protection for persons and property against electric shock 2. whether sinusoidal alternating fault currents or smooth direct fault currents - Siemens offers the right type for all requirements, as well as special variants.