Given that FSA has investigated more than 3,000 fires, we have come across a great variety of ignition mechanisms. The main causes, approximately in order of frequency, are electrical malfunction, deliberate, hot work, electrostatic and spontaneous combustion. There are separate pages with photographs showing examples, as below.
In many respects the photographs give a false impression, in that while they illustrate the ignition mechanism, the root cause can be quite different. For example a photograph of arcing between a conductor and a frame does not say why the conductor was in a position that it could rub and lose its insulation in the first place.