A Con Ed worker went berserk Monday, allegedly stabbing his ex-gal pal at the Upper East Side art foundation where she works before driving to the East Village and knifing two co-workers.

Trevino Terry, 39, allegedly stabbed the mother of his child the mother of his child, Alicia Sylvia, 36, at the Robert Sterling Clark Foundation at 2:30 p.m., law-enforcement sources said. She was rushed to New York-Presbyterian Hospital in serious condition.

Terry then drove to a Con Ed facility, where he allegedly attacked his co-workers who were not seriously injured, sources said. He was arrested soon after.