Residual current circuit breaker, 2-pole, type A, In: 125 A, 100 mA, Un AC: 230 V Residual current circuit breaker SENTRON 5SM3 for comprehensive protection of people and property against electric shock. The residual current circuit breakers offer reliable safety during installation thanks to the reach-around and contact protection included as standard. Optimum technology for your safety - only from Siemens.