Google Cloud PLC misconfiguration prevented London generators starting

Google Cloud revealed that a PLC misconfiguration and voltage-sensing design flaw prevented emergency generators from starting during an October 20 outage at its London availability zone. The incident occurred while primary feeder B was undergoing repairs, leaving feeder A to support the total critical load before an external underground cable broke. Although uninterruptible power supplies functioned temporarily, they eventually depleted their power, causing widespread service interruptions for UK institutions including Lloyds, HSBC, Royal Mail, and Revolut. Open article →