Huge blackout strikes Sydney

A substation fault has left 50,000 homes and businesses in north-west Sydney without power and is causing chaos on roads.

The fault at a Transgrid substation at Dural interrupted electricity supply to the main grid, causing a widespread blackout around 5:00am (AEST).

Suburbs including Hornsby, Berowra, Beecroft, Wahroonga, Epping and Cherrybrook have been affected.