Fire broke out around 6:30 am at the electrical station located on the mezzanine level of calender Z in a tyre factory. The site’s fire-fighters, were alerted by the siren activated in the guard house and intervened immediately. They quickly controlled the fire by using eight CO2 extinguishers. As a precautionary measure and in relation to the smoke release, the staff present onsite were evacuated to the exterior meeting points. External emergency services were called as a precaution and arrived once the situation had already been controlled. Some equipment (construction machinery, calenders, presses, etc.) remained idle during the investigation until rented emergency power generators could be connected by the operator. The fire, which broke out in the main electrical cabinet, was caused by an electrical problem on one of the low-voltage circuit-breakers. According to the operator’s investigation, the general short-circuit that caused destruction of the first column, containing the general breaker, was due to a temperature rise in the upstream rear pin that broke after just a few days of use following annual maintenance and restarting of the plant. Protections upstream of the high-voltage / low-voltage transformer supplying the electrical panel reacted perfectly: the fuses with a striker bar melted and caused the switch to open. Verification by thermography would have prevented the accident. The operator was planning on checking the other electrical cabinets to prevent any abnormal overheating. This accident follows the one that occurred on 20th August at the same site, on a new transformer with faulty coils (ARIA 33792).