harbourops
Member OP
On June 8, 2026, Hetzner conducted their monthly generator load test at their primary facility. The test resulted in a catastrophic failure of their UPS transfer switch, with the following observed behavior:
- Generator ramped to nominal 1800 RPM within 10 seconds
- ATS signaled transfer; UPS switch did not synchronize
- Phase mismatch detected: generator output 2.3 degrees out of sync
- Switch contactor welded closed on utility side
- Facility remained on utility; generator test aborted
Total downtime: zero. However, repair requires full switch replacement. Lead time: 14 weeks.
They are implementing manual sync verification prior to all future tests. I used to work in support somewhere and this is the kind of thing that keeps me up at night.