ConEd ties NYC blackout to a bad wiring job done 11 years ago

More than two weeks after a blackout plunged much of Manhattan’s west side into darkness, Consolidated Edison Inc. has identified the culprit: poor wiring.

Faulty wiring was installed 11 years ago between sensors and a relay system designed to detect and keep electrical faults from spreading, ConEd spokesman Michael Clendenin said in a phone interview Monday. It came back to haunt the utility July 13, when a 13,000-volt underground cable broke down and sensors failed to alert the system to open breakers and isolate the outage.

“There’s got to be appropriate wiring between the sensor and the relay — and it was not there,” Clendenin. “It was not done right from its installation 11 years ago.”

The outage left more than 70,000 customers without power, paralyzed much of the subway system, dar

kened Times Square and forced the evacuation of Madison Square Garden during a Jennifer Lopez concert. New York lawmakers have called for investigations of ConEd, which are ongoing. Mayor Bill de Blasio suggested a government takeover of the utility.

De Blasio and New York Governor Andrew Cuomo did not immediately respond to requests for comment.

ConEd has reviewed 15 years of operating data at the 65th Street substation where the blackout began, fixed the faulty wiring and has taken equipment out of service to conduct diagnostic testing, the utility said in a statement.