Most homes in Australia are now fitted with Residual Current Devices (RCD's), or as they are more commonly known as, Electrical Safety Switches. These are designed to trip (thereby cutting the power to that circuit) whenever a leakage is detected from that circuit. A leakage is caused when someone gets an electric shock, so the RCD will disconnect the current before permanent injury (or death) has occurred. However, it's not the only cause for a leakage, for instance a faulty appliance can also cause a leakage. Read the full article