Sydney left without back-up power after blackout chaos

Sydney’s central business district will be left without back-up power for “some months” while Energy Australia investigates the cause of yesteday’s two-hour blackout that plunged the city into chaos.

The power failure affected more than 100,000 people. Between 4.40pm and 6:35pm, lights and traffic signals were off from Circular Quay and The Rocks to Bondi, Rose Bay and Newtown.

The harbour tunnel and bridge were shut down, and fire authorities were called to 34 lift rescues after workers were trapped in office lifts across the city.

Energy Australia has said the blackout was caused by a fault in one of four major cables that supply power to parts of the CBD, the inner-city and eastern suburbs.

The fault triggered a shutdown in two other cables that service the area, plus the fourth back-up cable.

“This is a highly unusual fault in that when one cable failed a signal was also sent for the three remaining cables to shut down as well,” spokeswoman Kylie Yates told the Sydney Morning Hearld.

“That’s why we carefully and systematically checked those cables to make sure they were safe to put back online last night.”

The faulty cable will be out for some months, which means the CBD will be without a fourth backup cable in the event of a failure in the other three.