Fire marshals say electrical wiring for construction lights caused the smoky basement fire that shut down Manhattan's main criminal courthouse.

The fire Tuesday postponed rap star Lil Wayne's sentencing in a gun case, among other cases.

The Fire Department said Wednesday it has declared the blaze accidental.

More than 1,000 people were forced to leave the building. Eight people suffered minor injuries.

The courthouse is still closed. Many proceedings have been moved to a neighboring court building.