A fire broke out at about 11 p.m. on a set of capacitor banks of an electrical transformer in an aircraft parts factory. The fire detection system alerted the security guard who called for help after having confirmed the situation. The 15 employees present evacuated the building, and the fire brigade put out the fire. The transformer was destroyed, causing half of the production workshops to be without electricity. Two generators were started the next day, and production resumed normally.
The electrical fire occurred in a capacitor bank. The capacitors in question had a film structure in gel, contained in plastic cartridges within a metallic structure. Over time, the skins can deform, swell, undergo micro-priming and eventually catch fire. According to the operator, these capacitors require no special maintenance within 10 years. It is not necessary to conduct preventive checks because these defects would not be detectable. All the capacitor banks on the site were 7 years old but had been retrofitted 4 years earlier.
The manufacturer stated that the maximum lifetime of these capacitors is 10 years. Beyond that, one must be very careful. It recommended removing the capacitor banks from the technical plant rooms where other equipment is located or where cables are routed. The batteries must be installed in an adjacent fireproof room and cable routing openings sealed. The operator planned to replace its 10-year-old batteries and study the possibility of installing the others in a dedicated room.