On March 28, 1993, about 2115 hours Pacific standard time, a Cessna 172K, N758XY, had in inflight fire during cruise flight near Fresno, California. The fire was extinguished and the pilot was able to land the airplane safely. The airplane sustained substantial damage from the fire. The certificated commercial pilot and one passenger received minor injuries and the two remaining passengers were not injured. The personal flight was being operated by Mazzei Flying Service of Fresno at the time. The flight originated in Coalinga, California, about 2045 hours and was destined for Fresno. Visual meteorological conditions prevailed and a flight plan was not filed. FAA safety inspectors examined the airplane and interviewed witnesses after the accident. They reported that an unsupported electrical wire bundle was routed over the fuel line under the cabin floor. The wire bundle abraded on the fuel line and arced. The electrical arc burned a hole in the fuel line which allowed fuel to leak. The leaking fuel ignited. The pilot reported that he used the airplane's hand held fire extinguisher to extinguish the fire. The pilot said he diverted from Fresno Air Terminal to Fresno Chandler Downtown Airport. The pilot landed safely at Fresno Chandler Downtown Airport about 2020 hours. According to the operator, the electrical wire was installed prior to them obtaining the airplane.