The arc fault is well-known causes of electric fire incidents as well as electric treeing. In low voltage rating such as common home appliances, an arc-fault state can be achieved due to poor contact condition even if the contact is used within manufactured current rating. Therefore, a detection on such phenomenon is required to elevate electrical fire safety. We have researched the process of the arc fault in low voltage. Generally, the discharge on the tip of plug leads distortion of electrical waveform. One of the detection method for arc fault is to analyze the wave form in a plug. According to our research, the higher resistance of the contact area on the tip of plug due to oxide copper lead to high temperature area due to Joule's heating. In this presentation, we report how to detect series arc-fault in common household appliances. The derived method is to measure the energy consumption of the electrical appliance that has been affected with arc-fault. The power that was lost from arc-fault can be reliably measured at the load in the experiment. Therefore, a common commercial power-saving socket could be utilized for power measurement. Further development into the prototype phase is required to realize the new prevention method.