In this case, a fire started in the ignition switch of a car parked in a garage under a house. It was late at night, and the owners were in bed. The husband was awakened by their cat and went to investigate. He looked in the garage and saw flames emanating from the steering column. He was overcome by smoke and could not make it back to the bedroom. His wife was also overcome by smoke and both died from their injuries.

The ignition switch of this Ford vehicle, the subject of a class-action lawsuit, had ground and positive terminals very close to each other. As a slider moved over the various terminals in the switch, current from the fan circuit caused a small spark at the positive terminal. This removed copper from the terminal in very small amounts which mixed with the grease coating the contacts. Over time, enough copper was mixed in to make an electrical path between the terminals. As power flowed through this new path, it heated the plastic of the switch to a point where it caught fire.

These graphics and animations are part of a presentation we developed for another expert on short notice.