This case had been judged by the fire assessment committee that the photocopier was the ignition point; and the court of first instance determined it not to be the ignition point based on the report of this research. This case showed that the experiment data are very important to prove the fire origin during fire investigation and this research discovered that neither overloading nor short-circuiting of the cables of the photocopier would result in ignition of the wire on the interior, the plastic casing, or the paper around the photocopier. When using cables with various coatings, the results caused by overloading were drastically different. Under an overload to the cables of a Japanese photocopier, the copper interior snapped and the outer coating only expanded and cracked, but there was no fire nevertheless the high temperatures. In contrast, when using standard household cables (16AWG), they could not withstand the high temperatures and ignited, which explains the importance of the design for the outer coatings of electric cables. When combustible liquids such as gasoline were placed beside the photocopier, the gasoline would ignite if the photocopier was overloaded regardless of the type of outer coating. Results show that combustible liquids should be placed at a safety distance from electric appliances such as photocopiers.