RCD, 4-pole, type F, short-time delayed, In: 40 A, 30 mA, Un AC: 400 V. The RCD is the residual current device for protection against accidental contact. The patented residual current devices from Siemens are an important part of the Sentron protection components for electrical installations, as they prevent life-threatening electrical accidents by safely switching off dangerous residual currents to earth. Electrically ignited fires can be prevented before they even start. Whether through direct contact with energised parts during operation or indirect contact with equipment - protection is achieved primarily through rapid disconnection.