OVH founder and chairman Octave Klaba has provided a plausible explanation for the fire that had burned down its data centers in Strasbourg, France. The fire touched upon an Uninterruptible Power Supply (UPS) unit that had been serviced that morning. Klaba said that the UPS supplier had come in the same morning and restarted many pieces within UPS7, and changed many pieces in the unit. The company is working on cleaning up the premises and rebuilding the data center with their suppliers by adding additional resources.
Source: https://www.bleepingcomputer.com/news/security/ovh-data-center-fire-likely-caused-by-faulty-ups-power-supply/