The first time they flipped the switch on the ethereal spectacle known as the Tribute in Light, Ground Zero was still a disaster zone, only six months had passed since 9/11, and dazed New Yorkers had grown weary of funerals.

When the time came, there was little pomp. Opera legend Jessye Norman sang “America the Beautiful.” A few politicians made a few brief remarks.

“And then the lights came on,” recalled theatrical producer Michael Ahern, who, for a decade now, has orchestrated the tribute.

“People who were there — the construction workers, the recovery workers — told me they were immediately moved by it,” he said.

Workers yesterday began setting up the array of 88 7,000watt bulbs that make up the two columns, rolling them atop a parking garage a few blocks away.

The preparations will go on another week before the switch is thrown for this Sept. 11.