The insurer for Con Edison can sue the Port Authority of New York and New Jersey for negligence in connection with the destruction by fire of 7 World Trade Center on Sept. 11, 2001, a federal appeals court ruled yesterday.

Reversing a lower court’s grant of summary judgment, the U.S. Court of Appeals for the Second Circuit said the Port Authority can potentially be held liable in the $314.5 million suit for the installation of diesel fuel tanks at 7 World Trade.