Abstract: Using the experimental platform, the thermal characteristics and ignition capability of wires with different materials and cross-sectional areas under overload were studied under the conditions with or without of combustibles such as scrap paper and cotton. The results show that the temperature rise curve of the wire conforms to the trend of single exponential function in all cases. All final temperature values of the wire are generally divided into 4 or 5 stages corresponding to overload multiples.Copper wires with a cross- sectional area of 1.5 mm2 have the highest temperature. The relation between parameters of the fitting function of the wire temperature rise curve and the overload current multiple is linear when there is no combustible,and is quadratic or cubic polynomial when there is combustible.Under the same conditions, the final temperature of the wire is higher when there is combustible material. Except that the copper wire with a cross- sectional area of 1.5 mm2 had the highest temperature due to paper burning, the temperature of the other wire wrapped by cotton was relatively high under 4 Ie. Until the end of the experiment, cotton was only smoldering. The conclusions of this study can provide reference for the prevention and recovery of overload electrical fire and fire investigation.

Key words: overload, electric wire, heating characteristics, ignition capacity