Most of the sidewalk along North Park Place in Morristown was cordoned off on Tuesday afternoon because of a smoking manhole.
No power was lost and no establishments were evacuated.
“Everything is doing what it’s supposed to do,” said John Pawlo, an advanced engineer for Jersey Central Power & Light.
He explained that the problematic underground transformer near 10 Park Place tripped a circuit breaker, isolating it from the rest of the grid.
The smoke dissipated shortly after firefighters arrived at 3:32 pm, said Fire Chief Robert Flanagan. Police began re-opening most of the sidewalk to pedestrian traffic around 5:15 pm.
Morristown was plagued for years by underground electrical malfunctions and fires, including a flaming manhole that injured a Morris Township mom in 2011.
The state Board of Public Utilities directed JCP&L to perform upgrades last year. Since then, there have been no major incidents involving manholes. Safety tethers have been installed on some of them, to prevent them from shooting into the air, in a test program.