2pm FirstEnergy's Eastlake Unit 5, a 680MW coal generation plant in Ohio trips off.
3.06pm FirstEnergy's 345kV Chamberlin-Harding transmission line, in north-eastern Ohio, trips.
3.22pm Chamberlain-Harding's trip-out puts extra strain on FirstEnergy's 345kV Hanna-Juniper line, which heats the wires and causes them to sag into a tree, short-circuiting the line.
3.41pm An overload on FirstEnergy's Star-South Canton 345kV line in Ohio trips a circuit breaker at the Star switching station, where FirstEnergy's grid interconnects with a neighbouring grid owned by American Electric Power (AEP).
3.46pm AEP's 345kV Tidd-Canton Control transmission line trips where it interconnects with FirstEnergy's grid, at AEP's connection station in Canton, Ohio.
4.08pm Utilities in Canada and the eastern US see wild power swings.
4.09pm Power in the grid supplying Cleveland, Ohio plummets to zero.
4.10-4.21pm Nine US nuclear power plants and 12 non-nuclear US power plants shut down automatically after losing power, causing blackout.