RCD, 4-pole, type B, selective, In: 80 A, 500 mA, Un AC: 400 V The RCD is the residual current protective device for touch protection. The patented residual current devices from Siemens are an important component of SENTRON protection devices for electrical installations, because they prevent life-threatening electrical accidents by safely disconnecting dangerous residual currents to ground. Electrically ignited fires can be prevented while they are still developing. Whether by direct contact with operationally live parts or by indirect contact with equipment, protection is achieved primarily by rapid disconnection. The residual current circuit breakers are characterized above all by: 1. comprehensive protection for persons and property against electric shock 2. whether sinusoidal AC residual currents or smooth DC residual currents - Siemens offers the right type for all requirements as well as special designs 3. be standard-compliant g.