Pollution
Humain
Environnement
Economique

At 5:30 p.m., a smoke alarm went off at the transformer station in an equipment manufacturing company. An operator noticed smoke exiting the ventilation grilles and from the joints of the room’s door. He disconnected the electricity, initiated the fire procedure and called the fire department. The personnel were evacuated. The smoke dissipated a few minutes after the electricity was disconnected. The emergency services arrived at 5:50 p.m., opened the room and checked that there was no hot spot. At 6:00 p.m., access to the premises was authorised, and the evacuated personnel could return to the building. The workshop’s activities were resumed at 6:30 p.m.

The incident was attributed to the overheating of a capacitor bank. This overheating was linked to an accumulation of several factors:

  • scorching outdoor temperature;
  • the batteries were not shut down during the summer period even though none were needed;
  • the chosen technology (with contactors) was not the most suitable;
  • insufficient ventilation inside the room.

Following the event, the operator implemented the following actions:

  • insulation of the batteries in operation at the time of the incident;
  • development of a procedure to shut down the battery from April to October;
  • adaptation of the choice of contactors based on the type of equipment and respect of the replacement schedule recommendations;
  • improvement of ventilation by cleaning the air extractors at the beginning of the summer and creating an airflow into the bottom of the room.