Consolidated Edison Co. (Con Ed) said a relay protection system at its West 65th Street substation failed over the weekend, causing a blackout that affected more than 70,000 customers on the West Side of Manhattan.

Spokesman Allan Drury told NGI that natural gas was in no way involved in the incident, except perhaps a bit less burned at power plants in the region during the five-hour outage.

About 72,000 customers lost power around 7 p.m. ET on Saturday, and within three hours, more than half had their service restored, Drury said. Power was back on for the other customers within five hours.

Con Ed said an analysis showed when the primary and backup relay protection systems failed a faulted 13,000-volt distribution cable at West 64th Street and West End Avenue couldn’t be isolated, causing several electrical networks to fail. The system detects electrical faults and directs circuit breakers to isolate and de-energize them.

Con Ed provides electric, natural gas and steam service to 10 million people in New York City and Westchester County. The outage came ahead of scorching temperatures forecast for the region this weekend. Drury said there could be other scattered outages as a result of hot weather, but he noted that the warning is not related to last weekend’s incident.