Abstract: There is provided a power-off system including a connector (10) connected at one end thereof to a system power line (A) and at the other end to an electric appliance (10) and which connects or disconnects a power supplied from the system power line (A) to the electric appliance (100), a sensor (11) to detect environmental information, and a signal transmitter (12) to generate a predetermined signal on the basis of the environmental information detected by the sensor (11) and send the generated predetermined signal to the connector (10). For example, the sensor (11) having detected an earthquake will send an quake signal to the signal transmitter (12), and the latter will open the circuit of the connector (10) to prevent a fire possibly caused by the earthquake.

Abstract: The present invention relates to method for a detecting tracking short. In some embodiments, the method may include detecting current flowing on an electric circuit. In other embodiments, the method may include calculating the frequency distribution of the variation of the current detected in a predetermined period. In an embodiment, the method may include outputting a detecting signal in case the frequency of variations included in the predetermined range satisfies a judgement reference.