Google says a setup error stopped its London backup power
Google Cloud says a misconfigured controller kept generators from starting during the 20 October London outage, according to The Register.
The facts
- According to The Register, Google Cloud says a misconfiguration stopped emergency generators starting in its europe-west-2-b zone during the 20 October outage.
- The outage disrupted services at Lloyds, HSBC, Royal Mail and Revolut.
- Google says an external underground cable to feeder A failed while feeder B was switched off for repairs after a generator load test on 14 Oct 2026.
- Backup batteries (UPS) worked for about five minutes, but a voltage-sensing design flaw and controller misconfiguration sent no generator start signal. Google has reprogrammed the controller and plans faster alerts and wider testing.
Case notes · Danny's take
Why it matters
Cloud outages sound abstract until your bank app stops working. This one wasn't a freak event. It was a repair in progress, a cable failure and a controller that believed power was fine. Redundancy on paper is not redundancy in practice. Only a test under real conditions tells you which one you have.
For builders
Don't assume one availability zone, or even one cloud region, is enough for critical services. Check how your provider handles maintenance windows, and test your own failover instead of trusting the architecture diagram. Fast, honest status communication also matters when customers are waiting.
Not financial advice. Do your own investigation.
This story was summarised with AI from The Register's reporting and checked against our editorial policy. Danny's take reflects his views. Disclaimer.
Danny Walter
Founder of Moon Republic, Volt Terminal and Moon Republic Academy. Author of The Market Is a Crime Scene and After the Applause.