Google Cloud has revealed that the cause of the October 20 outage in its europe-west-2-b availability zone was a ‘misconfiguration’ of its systems that meant its emergency generators didn’t start. The outage at the London facility caused service interruptions at outfits including Lloyds, HSBC, Royal Mail, and Revolut . In a November 4 update to its service status page, Google explained what went wrong. “The site relies on a 2N utility power architecture — where the facility has complete duplicate power paths for every critical load — backed by a central high-voltage generator bank managed by a dual-redundant Programmable Logic Controller (PLC),” Google revealed. The facility gets its juice from two independent utility feeders, which Google calls “A” and “B”. There’s also a “standby utility connection configured for manual campus-wide transfer during maintenance operations or emergency events.” Google says the root cause of the incident was failure in an external underground cable through which its power supplier brings ‘leccy to its bit barns. That cable connects to primary feeder A and it broke at a time when feeder B wasn’t working. “Circuit breaker feeder B was physically opened to allow for corrective repairs following issues identified during a quarterly generator load test on 14 Oct 2026,” Google admitted. “Consequently, primary utility feed A was supporting the total critical load while the feed B breaker remained in an open position to allow repairs to be conducted on the B feeder pathway.”…