Single phase energy safety monitoring instrument detects the 2 major parameters that cause electrical fire,residual current and wire temperature.When the aging of the wire causes the insulation layer to break,leakage current will be generated, and excessive leakage current will cause the wire to heat up, thereby causing fire. At the wire connection, due to the long thermal expansion and contraction time, it will lead to poor contact, and in the case of poor contact, large current will increase the wire temperature, resulting in heat generation, resulting in fire.