Con Edison of New York has concluded that a strong lightning strike in the vicinity of a Queens substation was the cause of the June 27 power outage that affected 136,700 customers on the Upper East Side and in the West Bronx.

Information obtained from real-time lightning tracking data show that detection instruments measured a lightning strike of 34,000 A in the vicinity of a substation in Queens at 3:42 p.m. on Wednesday, precisely at the time of the power loss. The lightning strike momentarily affected communications equipment that prompted circuit breakers on multiple transmission feeders to open, causing the service interruption.

All other electric system components operated properly to contain the event from spreading and protected equipment needed for service restoration. As a result, power was restored to all customers within 48 minutes at 4:30 p.m.