There were three substations on each side of Manhattan and one in the Bronx.
Consolidated Edison, which lost two substations in the attack, has installed 36 miles of temporary cable.
That substation feeds two substations on the west side in Lower Manhattan, which serve Battery Park City, SoHo, TriBeCa, the West Village and Greenwich Village.
Two substations that relayed electricity to much of Lower Manhattan were destroyed Sept. 11 when 7 World Trade Center collapsed.
(Before Sept. 11, Battery Park City and some parts of TriBeCa were served by two substations that were destroyed in the collapse of 7 World Trade Center).
Con Edison officials said the power failure was caused by two substations on the Lower West Side that were knocked out of service because of the blaze.
The company's major computing centers in Newark and Secaucus, N.J., each receive power from two substations to ensure a steady flow of electricity.
Flood defences were overrun in Carlisle, where 4,000 properties had no electricity, and police said there was a "major risk" that two substations could flood – cutting power to 60,000 homes.
Some of its elite engineers help protect power grids, telecoms networks and other critical infrastructure in America against cyber-attacks and other threats.The lab boasts its own 61-mile (98km) electrical grid and seven substations.
Electrical, gas and steam service were normal throughout the city, except for the areas affected by the loss of two substations that were knocked out when 7 World Trade Center caught fire and collapsed.
