RCDs (Residual Current Devices) are safety cutouts which prevent the "leakage" of fault current and are mandatory for all new power point and lighting cables in the home. And for good reason – they save lives and property. RCDs constantly monitor the flow of current along mains cables ensuring that no current passes to earth (the most common cause of electric shock). Any small passage of current to earth, (typically 30 thousandths of a volt), whether it be from a rat chewing a cable or a faulty appliance results in the circuit switching off. Choose from switchboard mounted RCDs (best value for money) or a variety of sockets and wall mounted RCDs.