The latest blackout came just one week after 840,000 customers were left without power after a single tree fell on another power line in the center of the island in a major outage caused by the same subcontractor, according to officials.
"This is the second power failure that has affected the people of Puerto Rico in less than a week", Rossello said. On Wednesday, an excavator used by the contractor hit a transmission line near the south coast.
Last October, PREPA signed an initial $200 million contract with Cobra Acquisitions to restore the main lines of electric transmission across the island. Within hours, long lines were reported at local gas stations and gridlock at some of the larger intersections in the San Juan area.
Tesla has been shipping Powerwalls and Powerpacks to the island of Puerto Rico since Hurricane Maria struck.
"Hurricane Maria produced the largest blackout in U.S. history, according to a study released last week by Rhodium Group LLC, an economic consultancy", the Wall Street Journal reported. He said the company hoped to have service restored by midday.
Officials said restoring power to hospitals, airports, banking centers and water pumping systems was their priority.
The outage did not stop the last of a two-game series between the Cleveland Indians and Minnesota Twins being played on the island. Cobra, a subsidiary of Mammoth Energy Services, is based in Oklahoma and was formed last spring. This led to an electrical ground fault that caused the outage of the transmission circuit that caused the island-wide blackout.
Rivera said he worries that such serious power outages are still occurring as the new Atlantic hurricane season, which starts on June 1, approaches.
As of this afternoon, we're told there was zero percent power generation on the island.
"We respond to get things back up to normal", Lt. Gen. Todd Semonite said.
The U.S. Army's top engineer said in February that their role was never to completely rebuild the power system.
Right now, all of the focus is on bringing the main generators back online. but this is a frustrating time not only for the relief workers but for the citizens themselves, since almost 40,000 are still without normal electricity as a result of Hurricane Maria.
"The outage snarled traffic across the island, interrupted classes and work, and forced dozens of businesses to temporarily close, including the largest mall and popular tourist attractions like a 16th Century fort in the historic part of Puerto Rico's capital", Coto wrote.